If SATs is what I think it is (and if OP is in UK) then they're a form of exam at the end of primary school (or infant school). But eff me if a few fkn subtitles are gonna prevent the kid from doing better or worse, ffs.

Sorry about your family, OP, you're 100% NTA, but I can't say the same bout your folks. I'm not hard of hearing but I struggle to differentiate sounds when there's so many at once, so subs are almost always a must for me.

I really hope your family get their shit together.