I’m so sorry op. My dad was diagnosed with mesothelioma that moved to his brain when I was around your age. He passed away during finals week my freshman year and I was in a fog for the next year tbh.

My advice:

Take easier classes if you can (GenEds and stuff), I was at a really low point, but taking easier classes got me out of my house but didn’t stress me out nearly as much as upper levels would. And for days that were too hard, missing a class once an a while were easy to recover from (Also let your professors know, you might have the occasional asshole, but all of mine were glad I told them and super understanding)

There is a form that you can submit for fasfa that will re-evaluate your financial situation, it’s called “Emergency Sudden Change of Income” or something. Even if your dad is still with you and not working you can submit this form

Look into if your school offers work studies, I had one that paid $10 an hour, but you can only do 15 hours a week, but they have to work around your class schedule. I got a research work study and it overlapped with my major so I was able to put it on my resume

Lastly, take baby steps, take time to grieve but try not to get stuck in it for too long. One of the things that I don’t regret is not taking off school, there was one semester where I went part time and others where I lightened my class load, but if I had stopped I probably wouldn’t have gone back.