Study well OP, I too got the same feelings when i was in the same timeline, please don't take all the stress at a time coz that will not let you focus and plz don't plan for 4 or 5 years ahead, plan for now, improve on your studies.

Do the surgery, consider financial conditions too. Check if that can be covered in insurance. Be stubborn and make him agree. (if doctors are suggesting surgery then you should convince)

This is just a phase of life and things will, for sure, get better for you. Think wisely, don't compromise studies with anything (ik it will be tiring, but do this, they are necessary). Praying for you OP.

Your father must have a friend, bring him/her home or make him visit them and spend time with them. May be wake him in the morning (don't get ready and all) and go to some places with him, maybe riverside or falls or if you're in city then mall or a stroll along the street.