I guess maybe because one was like his "little brother" while the other was like his "father" but in all reality it's all the same. It's family in his eyes at the end of the day.
All 3 grew up together, all 3 were in the same game. All 3 from the same neighborhood.
And his reasoning behind killing Rolla was because he thought Rolla was trying to move in on his shyt and take over. Obviously it was cuz Kanan got in his ear and told him that's what was going on but hey he had a real reason regardless
Kanan not dying is
I can see why people think it's lazy writing and 50 trying be all in the show.
But to his defense he really not all in the shyt and hasnt made it all about him yet. He always gives credit to Courtney and the actors