Your feelings are so normal and legitimate, and also very understandable. You have gone through so much with your dad. He wasn't always the nicest to you either, and even though two wrongs don't make a right, it is difficult to not retaliate. I also think that when a loved one is sick (or dying) we always think of how bad we have been (satan makes sure we have those thoughts) and never the good we have done for them, I have done that numerous times regarding my dear mom and dad, but, I do know that I did help them a lot. I know you wish that he could be home and all could be "normal" but sadly, I think those days are over and it is hard to accept. It would be extremely difficult for you to take care of him, he needs someone to can help lift him should he fall, and just to watch him and do what is needed on a daily basis. it is hard to finally come to that realization and it hurts so damn badly.
In regards to God punishing you, I know exactly how you feel, I often feel like God is punishing me as well for things I have done in the past and it is really upsetting at times. People tell me that He doesn't do that, but as you said, who really knows. I am embarrassed to say that I did not treat my dear mother too well one day and unfortunately, it wasn't too long after that that she died. She just refused to try to do the exercises on the leg that was amputated so she could get have a prosthesis made. I got so angry I yelled at her at said "To Hell With You, To Hell with YOU!!!!" oh my, she was in tears, I thought my dad would kill me, it scared the dog. She called her sister and she tried to calm her down. I was in tears and miserable. I had been working with her so long and trying to get her to do the exercises, I was totally burnt out, but that did not give me a reason to say what I did. I don't think I apologized until a week later when she was in the hospital dying and in a coma, then I kept saying "I am sorry, I am sorry, please forgive me" I am sure she did, but to this day, it haunts me and I remember it. Now, is God punishing me? I don't think so, not now, but, He does allow us to live with the consequences of our sins, and in my sin, it is deep sorrow. So, Shazia, if you have asked the Lord to forgive you, and in your case, gone to confession, I am sure the Lord does forgive and is not punishing you, but, you will have to live with the consequences and that is feeling horrible about it once in a while as satan likes to remind us of our sins. I hate words, they say that don't hurt, well, that is crap, they DO hurt, more than anything and a person can NOT take what they said back. So, I guess the Lord is not punishing us, but He does allow the consequences of our sins to occur, we punish ourselves.
Right now, the only One who can help you is Jesus and the Holy Spirit, keep praying to them, I am praying for you as well.