Accepting the people we love to have negative feelings

I’m traveling a lot and, for that reason, I’m not often around my dad. He’s 81, and tells me sometimes that he won’t be around much more time.

I may have a manual (that I’m challenging!) for being a good daughter. I think, “he’s sad that I’m not around him more often.”
Deep down, I’m comfortable with my choices and absolutely love my reasons for having that lifestyle.
But sometimes, I still feel the guilt and sadness because I think thoughts such as “He’s sad I’m not around” or “I wish he would understand” so that I can feel better 😉

Could you guide me a bit more on that please?
The best would be to accept that he’s feeling any feelings, they are valid!

Thank you so so much!