My dad passed away, and I felt very regretful and sad. I really felt like the sky had fallen and I had lost all confidence in life.

Being able to realize your fault like this (knowing that your father has a bad heart but still arguing with him) shows that you have grown up and become sensible. We all probably made similar mistakes when we were kids. However, I think you have tried your best to take care of and love your father. Everyone is subject to birth, old age, illness and death, some early and some later. So don't blame yourself too much. As long as you have tried your best, that’s all!

Don’t do stupid things that make the living sad (you have other relatives) and the dead upset (your late father would never want you to do that), no matter for the sake of the living (including yourself) ), or for the sake of your deceased father, you should live well and live happily. This is the greatest comfort to the deceased!

Are you right?

I sincerely wish you can start living with a new look as soon as possible! (Personal opinion, please forgive me if what I said is inappropriate)