Dad in assisted living

Hi! I am struggling with my thoughts around an issue related to my father. My brother and I just moved him to assisted living and we will either have to pay most or some of his expenses there. I feel very resentful because my Dad made plenty of money in his life and never chose to save any for his retirement. He also cleared out a trust fund intended for my brother and I that his father had left for us. Intellectually, I know that there is no point in feeling frustrated but I still do. I have made saving for retirement one of my priorities and have a large account that will more than provide for me in my old age. I see this as a gift to my own children but essentially makes me feel that my Dad didn’t care enough about us to do something similar.
Current model:
C: Dad is in assisted living
T: I should not have to pay
F: resentful
A: not be very nice on the phone with him
R: don’t feel like a good daughter

Intentional model:
C: Dad in assisted living
T: I am lucky I have the resources to help
F: Grateful
A: pay his bills
R: Connected to Dad and proud that I am compasionate?

Any ideas or help on how to get from one model to the next? Also, any thoughts on the model in general would be helpful. Thank you!