I am sorry they are driving you nuts.
My opinion is there is a lot going on here besides the money/hotel issue. Maybe they just plain do not want to vacation with you and are saying they can't afford it as a way to try and get out of it. Maybe BIL wants to participate but his wife doesn't or vice versa. I'm not trying to be harsh or rude. Maybe they would prefer to save their vacation days for trips for just the two of them or with their kids alone. DH and I do not wish to ever travel with anyone else -- family or otherwise. And, I'll be honest again, going on a trip for someone in our family celebrating their 40th bday just wouldn't be a high priority of ours.

Especially if that family member already did a big trip to celebrate.
I have to agree with Carrie on this one!
No one in my family takes big trips for a 40th birthday, how lucky are you!!
Every year my parents, grandparents, aunts, uncles, cousins, close family friends, boyfriends, girlfriends...you get the idea, would rent a house on the Oregon coast for a week. We would all stay in this one house, until we grew in numbers that we needed 2 houses and we would split the cost of the house. My parents used to gripe that one of my aunts wasn't paying her fair share and was basically allowed to stay for free because she "couldn't afford it". Meanwhile she's driving a Lexus and sporting a diamond the size of glacier.
My feeling then and now on my Aunt's behavior and lack of ability to pay her fair share was that she was just after attention. She wanted everyone to feel sorry for her & bend over backwards to accomodate her and her kids. Which is usually what happened.
So what I learned is that you have a few choices;
either stop inviting them and taking trips with them (my vote!)
invite them & give them an itinerary of what is taking place for YOUR special bday trip complete with hotel, meal reservations and cost summary *this option works best if you are paying for all or most of the trip
OR invite them and let them do their own thing but request that they meet up with your whole family for one night to celebrate your birthday.
As far as the whole money issue...just stop worrying about it. It's not your place and you'll make yourself crazy. No one really knows what goes on in someone else's home so when you make an invitation (to any event) do so without conditions & be happy with outcome.
BTW- my Aunt ended up going to rehab, losing her tiny condo, getting a divorce, remarrying a man for money that she doesn't love, moving in with my grandparents, watch her own children go to rehab & follow in her footsteps ALL the while she clung to that stupid Lexus! She had nothing but she had her Lexus....so really, you never know what's going on & thinking you do is a mistake.
Family can suck but sometimes you have to learn to live AND love in the moment. And for goodness sakes....enjoy that birthday trip!!!
