Plot hole, sort of **SPOILERS**
When Dad has the guys from the funeral home pick up Grandpa's body, he tells a tale about "we thought he was just napping" and so on. They drive off with Grandpa and we hear no more about this. Wouldn't the fact that he was in a hospital gown seem odd to the funeral home staff? As well, he would have punctures from needles, and possibly lines still in place, since the ER tried to rescusitate him? And continuing in that direction, in any county that I know of, his death would have been a coroner's case, since his demise was unexpected and he had no attending physician (that we know of anyway). The ER would have wanted to keep the body, not try to dump it as soon as possible.
Next time you see me, it won't be me