Yeah I can see what you mean about love/hate with him.
Jason & Sonny scenes I've watched recently in 1996 makes me sad how much the writing is what ruined Sonny mostly for me.
I also think that Sonny was more like a father to Jason then than a brother.
Sonny tells Jason he should tell Juan in 1999 what is really like being his son.
Jason of course pissed Sonny off more by talking about all the good things Sonny had done for him over the years.
I think b/c Jason did see him back then as a father to him explains a lot more why he was so loyal to him.
He talked about back then even how Sonny taught him so much about life in general.