Wow, Leila...babygirl, y'all have been through and back, huh? Thank God your dad survived surgery, as it sounds touch and go. As I said earlier, stay near him if you are allowed. I know that ICU has rules, but talk to him and touch him softly to let him know you're there.
Bless your heart...I know the stress and fear you're in right now. I lost my dad just days before 9/11 terror attack. My mom is 89 (on May 1st). I've run the gambit with her from congestive heart failure to an insulin coma. I've fought the medical personel to treat her aggressively and bring her back from literally death's door.
It's not an easy feeling in your gut, I know. You're right...adrenalin kicks in and we step up. I don't know your dad's age. However, it's always my feeling, no matter the age...If they still have the "pursuit of health and happiness"...I FIGHT like a tiger to advocate. I know you are too.
Just remember...even we tigers need to feed and lie in the shade from time to time. Take care of yourself and keep us posted!
(((HUGS)))