Guilt as my dad is deathly ill

I've visited my dad once a week for the last year in his. Nursing home. The year prior to it I visited twice a week. Sometimes he'd act irate and rude over little things but mostly it was a good visit. My sister said why not go once a week after he acted like that, especially since he turned a cheek our whole life when we were severely abused by our mother. So I said, yes I'll do once a week.

But now that he has aggressive cancer and could pass any day, I'm feeling a bit of guilt. Every visit, and now too, I do provide him kindness and snacks, getting what he needs etc. , music ...but of course there were extra days last year I could have gone as well. 🙁