I'd try to make this short and sweet, but there's no sweetness in it, as I am fairly bitter to this day. MIL died 7 months ago. Let me say upfront that MIL could be a PITA and that she was no peach as a MIL. But whenever she got sick, DH and I were always there to be her advocates because that's how we were both raised. You take care of your parents. You do right by them. She was his mother and she deserved for us to do the best we could for her in her last days, since she couldn't speak up for herself.
One BIL (MIL's son, I mean) was right there with us in every way. He had been her caregiver, along with us, since her DH died 20 years ago. The other BIL, who could not get far enough away from his mother and shirked all responsibility for her while he laid it all on us, decided to show up the last few weeks of her life and try to run the show since he was the eldest son. Well, too little, too late. Plus, his ideas were a 180 from ours.
Keep in mind, the BIL we get along with had the medical POA. Yet every time, that BIL left the hospital for a break, obnoxious BIL changed the orders and had MIL's pain meds decreased to the absolute LOWEST the doctor would advise, spread apart as far as allowed. In other words, he was as stingy with the pain meds as possible. The other 3 of us felt that since MIL could not communicate whether she was in pain or not, we should err on the side of caution and give her a decent dose lest she experience any discomfort. I wouldn't want my own mother in pain, and MIL deserved the same protection. Yet BIL insisted,
"The minimum amount is sufficient." Prissy little twit.
Seriously, it was childhood all over again and was a power play to him. Could he "win" the battle over his brothers? He didn't give a rat's hiney about what was best for MIL, only that he prevail. For that, I will never forgive him. It was heartless and cruel. I have no use for him. I told DH that if BIL is ever in the same situation as MIL, we should tell the doctors to give him a Tylenol every 12 hours maximum, since that is "sufficient."
As for the funeral arrangements, thankfully neither BIL cared to have any part in making them, so it fell to DH and me.....mainly me since DH was at the hospital so much. MIL was not necessarily a vain woman, but she always wanted her hair dyed and no wrinkles.

She was without fluids for 3 weeks before she passed and looked beyond horrible. There was no way we were going to let people see her like that, since she would have hated it. No funeral home could make her look acceptable. I did tell them to dye her hair anyway, because I'd promised her years ago I wouldn't let her go to her grave with gray hair. DH got a look at her before the visitation and from 40 feet away stopped in his tracks, saying she looked atrocious and she would not want anyone to see her. We kept that casket closed tighter than a drum. If BIL would have argued the point, I'd have taken a plug out of him. If the deceased would not want to be seen in that state, then DON'T do it. Have some respect for THEIR opinion even if they are dead.
As for the meds issue, I sympathize. My mother used to say, "God made doctors and scientists smart enough to invent those medicines for a reason. We need to use them."

God bless her wisdom. For crying out loud, the woman is dying. When in doubt, medicate to eliminate any chance of pain or discomfort.
I am so sorry you have to experience this and even more sorry for your grandmother.
