Wondering if anyone has experienced this

My beautiful Bella died this past Saturday she was the boss cat and everyone knew it. Well now I'm thinking maybe my boy Severino is trying to establish that he is now the boss, because he has been going after Sophia a lot not aggressively no biting or scratching he Would NEVER hes real sweet! He just chases her constantly and shes hissing and growling this NEVER happened when Bella was alive. And my indoor/outdoor guy doesn't have a clue! Any thoughts?

It sounds to me as though he is improving his station.

Went through it twice, Spaz asserted herself after BC passed away, then again after J's Whiskers passed away, my Spaz and his Shadow were vying for alpha.
Shadow let Spaz take the spot I think mostly because of her age (and the fact that she has claws, he doesn't).

It took a couple of months for everyone to settle into the new order.
I would not worry as long as no one is getting too stressed.

I guess I just always thought Girls took charge!! Maybe Sophia is too timid Bella would Bop the boys in the head if they got to close and they NEVER messed with her but they mess with Soph!