Even thought it wasn't mentioned but implied that Elizabeth's mother Anna suffered from Alzhemiers which was rather sad that she wasn't able to remember since it is a rather difficult disease to go through.
Well the grandfather was kind of a prick, but he was also watching his daughter die right in front of his eyes, so he does have a pretty good excuse to be in a bad mood.
Frankly I would have clocked Sid too if I were him. Yeh yeh I know he is supposed to be a pretty stupid 17-year-old but even stupid 17-year-olds understand that people get old with Alzheimer's or dementia and sometimes say stuff they do not understand -- they are not trying to do comedy routines.
Scott of course does go too far with the 'she was a good girl, a faithful wife' stuff, but fathers always think their daughters are perfect little princesses. WE the audience know she was cheating and was not a faithful wife, but Scott does not. Matt knows there is nothing to be gained at that moment by throwing the truth in his face so he just bites his lip and goes along with it.
With his wife in dementia, Scott has to absorb pretty much the entire emotional impact for both of them. At the very end where he kisses Elizabeth goodbye and then looks through the door-crack right at Matt, you know he really did love his daughter.
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4) You ever seen Superman $#$# his pants? Case closed.
He's an old guy whose daughter is going to die because of a stupid accident she was probably mostly to blame for herself. He is basically spewing blame on everybody else within earshot (Alex, Matt) because he can't face the fact it was probably her own damn fault.
The main function of Scott is to show what patience Matt develops, to keep his mouth shut and bite his lip while Matt keeps spewing ignorant crap to splatter the blame on everybody else. When Scott comes out with the 'you didn't provide thrills at home' line, Matt had to be right on the trigger-edge of punching his lights out.
But Matt knows Scott is a crotchety old SOB who is now way more crotchety and bitter because of the imminent death of his daughter, and he knows to blow up at him will mainly poison his granddaughters against him forever, so he just sucks it up and lets it go.
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4) You ever seen Superman $#$# his pants? Case closed.
I don't think he feared loneliness. I think just the opposite. Anybody that hateful and cranky has probably already spent most of his life alone. Nobody who acts like that has or wants friends.