It's just dragging out

We unhooked my FIL last he suffered a major heart attack and died for for 20 minutes before they got him back after all the testing and everything they have found out he is brain dead. During the night his oxygen levels went down to 40% but now are up in the 70s the Drs said it could take days for him to pass. This is killing my husband. I just wanted it to be quick for all involved especially for my FIL.