Well, I'll try and keep this going on a weekly basis and rounding up all the most definitive news and rumours regarding the MCU.
As per the title, I got IW on Blu-Ray today. I saw it in the cinema, but my 13 yo son and 10 yo daughter have been pestering me to watch it. After thinking about it a bit I decided they'd be OK. I've been selective with what Marvel films I've let them see so far. They've seen Avengers 1, Antman, both GotG, Spiderman, Black Panther and Thor Ragnarok. And they liked all of those, but I've generally kept them at the lighter end.
So we watch it and they're loving it. My daughter was a bit shocked when Loki died, but moved on. Loved it when the Guardians rescued Thor - Rocket and Groot are her favourite.
She had seen movies with characters dying in it before. She loves Harry Potter (movies and books) including the end of Order of the Phoenix and Half-Blood Prince, so it's not completely new ground for her.
Then we get near the end. She gets upset when Gamora is killed. About then, I start thinking maybe this was a bad idea. Ask her if she wants to keep watching, she says yes.
She gets really angry when Quill wakes up Thanos, and when Strange surrenders the Time Stone. She was shocked when Stark got stabbed, but not upset.
Then the snap happens. She's in shock. Devastated when Groot dies, and Spiderman. The credits roll, and she's sitting there in shock and tears repeating over and over "this is a bad movie, this is a bad movie".
My wife and I try to comfort her, remind her it's just a movie, that it's not really the end of the story because there's a second half coming. Make the comparison to Half-Blood Prince vs Part 1 of Deathly Hallows. No dice, still really upset. Even tell her that there's already another GotG and Spiderman film in the works so they must be going to resurrect them somehow, still didn't really do anything to make her feel better.
After half an hour of comforting her, she calmed down, but was adamant IW is a terrible movie and she's still a bit upset now a few hours later.
So, I'm in the running with Thanos himself as father of the year.
Edit: what really upset her, I think based on what she said, was not (just) that characters died, but that "the bad guy won". Guess that's a story trope that we all are surprised by at some point.
I want Captain America to give a braveheart/Lotr pre-battle speech. Before the final battle, everyone is there, and everyone at that moment is an avenger. At the end of the speech is when Cap says “Avengers Assemble” and they all give Thanos the business.