The easiest way to avoid regrets is to ask yourself this question, "If not now, when?" It's a powerful way to put life and our decisions about how we spend our time into perspective"
Hopefully he can rise above the depression and start feeling better. You need to remind him that he has just had major surgery and what he is feeling is natural for anyone that has come through a surgery like this.
Stay strong Krista. This has to be so hard for you to see your sweet dad like this. Love you. (((((HUGS)))))