I need help with my father. ?.?.?.?

So in march my father had open heart surgery, to replace a bad aortic valve. This was an emergency surgery and it scared whole family and he almost died and it was horrible. But he did fine and came out. Ever since then he has beeen differient (in a bad way). He has been mean towards me, my grandparents, my stepmonster, and his friends. From what I've read online many people who have open heart have severe depression afterwards. We cannot get him to see anybody, he says if they aren't going to offer it to him (depression meds) he isn't going to talk to the doctors about it. I know he is stressed because he has over 150k in medical bills (no insurance) but were working through it. I just can't understand why he is being so horrible. He was going to shoot our new puppy bevause it tripped him and I had to take him to my moms. I came to my dads yester day (were at the fair because we show goats (sadly) when I got here he just gave me a look and walked away. He was going to divorce my stepmonster because she started being friends with HER cousin that he doesn't like, and my stepmonster was in her wedding. I just don't know what to do. He yelled at my grandfather beacuse he didn't put in a fence right (a big no no.) He hasn't even really talked to me. He's just been giving me dirty looks for 2 days. We can't get him to do any counseling or therapy, it is even free at the church but he thinks he's too good to go to church even though they supported him and made a colection jar for him when he was sick. I just don't know what to do with him anymore. I'm at my witts end. I can't get him alone to talk to him, and Ive been trying to get him tk be reasonable but he won't. And btw he won't talk he yells about everything... he is just ALWAYS yelling. Does anybody have ang advice?