You won't come back early from your vacation if your FIL dies and the only reason your husband would go to the funeral is to make sure he is not cheated out of half of the estate?
Wow.
I can understand that. But now it looks like all she cares about is the vacation and all her husband cares about is the money. It sounds a bit cold to me. Just my personal opinion.
Count your lucky stars that you don't have family that makes you feel that way. Or rather, takes away all positive feelings so that all that's left is that.
"I don't like you, you were a mean jerk when we needed you but...... we want what's coming to us $$ wise"
That sounds a little tacky to me.
From watching what happened with my FIL, they held inheritance up as the be all end all. He and MIL controlled their kids with it. "If you don't do such and such, you're out of the will." And they did take the kids out of the will at various points. The oldest son was out for 5 years after his then-boyfriend outed him to the parents (he's now back in MIL's graces). I'm sure DH and his sister were out, then in, at various times. They held it over their heads....
And then when FIL died, there wasn't even life insurance, let alone money in the bank. Let alone a paid for house. The only thing there was was a RV timeshare that we couldn't afford (and no one else wanted it), a broken down RV with a huge interest loan on it (BIL had to get it running enough to get it to the bank's parking lot so it could be repo'd), and 50K worth of IRS debt that I was the happy person to find out about during an hour-long phone call to the IRS on behalf of my MIL. Then I was "shot" b/c I was the messenger.
The inheritance is the ONLY reason the kids stuck around...and it was nonexistent. Which makes it alll....nothing. FIL was a horrible father and a rotten husband, and he was a nice grandpa, but part of his niceness was giving money to the grandkids...but it turned out that he was stealing from MIL's life insurance policy to fund their lifestyle (we actually found the signature-practice papers in his files).
I say all this to say...some people are just rotten.
I still don't know why DH went to FIL's funeral. He was sad b/c there was never closure to his grievances (if only his family had celebrated Festivus, ha ha). He was sad b/c of how FIL was with DS. But other than that, he went because it would have been no end of Hades with his mother if he hadn't. She still "makes" him (though this was the last year, he and his brother made it quite apparent to their mother that it was the last) go to the life-celebration things she gives every year (this was the 3rd year). I haven't gone to one of them, though i did go to the funeral (Buddhist memorial service).
So listen. My very very loved mom died, and I almost didn't go. Funerals are....a big ball of horrendous junk. I *hated* her funeral. I'm sure she wouldn't have minded. Getting to hear person after person put their feet in their mouth about heaven and all that, when I don't believe in it and she knew it and was OK with it, when the ONLY thing to say to someone is "I'm sorry for your loss", and later, realizing that my stepdad basically met his now-wife at that post-funeral reception...useless and awful.
I dealt with it alone (b/c I was single and dating inappropriate people back then, and there was no choice). But the funeral...even when you care about it, even if you're crying, you're still numb. And I know I don't remember anyone who was there...I know that a few people were there, and I remember seeing that there were lots of people there, but I don't remember. Oh, I remember a convo with my aunt, and sitting in the back room before it with my brother and SIL.
The hard work, the time you need someone to help you through...that's in the days, weeks, years after. When you get sad and need someone to just KNOW, and not ask "what's the matter?". When there's someone else watching the calendar and noticing that a birthday, a deathday, another important day, and to be extra gentle with you leading up to that. That's the important work.
The funeral is a couple of hours. The big stuff is the years after.
DH, even though he had a relationship very much like your DH and FIL's, has had some hard times. And THAT is the time that he needs someone. He WISHED I had stayed home. He knew it was going to be awful. I didn't help him, especially b/c I had our little son and stayed in the basement of the temple playing with DS except for DS's command performance when MIL made him bow to a picture of FIL. I wasn't needed, though I did drive.
That's a lesson I've learned...don't drive yourself to a parent's funeral.
The funeral didn't matter. The years since then have mattered.
This is ONLY between you and your husband. You said he wasn't that upset, or something like that. If it's just the driving thing, find a way to get him there, if it happens, without driving. Seriously...I was run off the road by a woman driving her extended family to her father's funeral...don't let him drive himself. If he really does want you there to help him, well...I would be really torn. But you know...your mother is important, too. And it sounds like she's elderly, and it's important. So...it's hard! Nowhere near as black and white, IMO, as others make it seem. Then again, maybe they haven't been through the situation.
This will happen with MIL someday. It will be confusing. I personally don't know why DH still has her in his life, she was just awful to him for a LONG time. She's been awful to me (and I almost never see her, she knows why).
When this happens...you can bet your bippy DH is going to be there partially for the "inheritance", which is only jewelry, frankly. Why? Because it was held over his head his whole life. It was MADE to be important to him. (and b/c his sister hangs with heroin addicts, would sell huge rings for a pittance and the money would be gone in a day) It might seem cold from the outside, but frankly, unless you've met people that rotten...you just don't know what it's like. Good gravy; at the memorial service for FIL, DH and his brother were standing in the back, aghast at the history being rewritten about FIL as their sister and mom went on about how FIL was in nirvana...meanwhile they were wondering if the cockroach he'd come back as had been hit with Raid yet. That's the kind of father their dad was.... And at this year's memory thing, it was all said out loud to MIL... Fun!
I'd take "we're going to an amusement park" out of the thought process. It's easy to say "disney vs funeral, how can you even ASK such a thing????"
Rather, see it as a once in a lifetime (given your mom's age) family gathering/event, being there for many living beings...vs being there for a few hours on one hard day, when the hard work of mourning barely even starts at the funeral.
That did it for me.
It sounds sad to me 
