Oh no! Sorry about the family drama! If you’ve read my book, you know that I know what you’re talking about haha.
As far as your room goes — the real key to minimalism is first going through all your stuff and getting rid of the excess so you’re only left with the things you really love and need. For decorating, the low ceiling shouldn’t matter as long as you give yourself a cozy rug, some beautiful bedding, and some accent pieces and art that are in the minimalist style. I’m sure you and your parents will love it!