it could be those dramas where the first marriage was a political one and hes been in love with Trina all along and only realising now when she got sick. Maybe Trina is just secretly in love with Gabriel too.
As I mentioned in response to another comment. I think it was basically transference. He was mistaking close friendship for feelings of love because his wife and companion had just died. That friendship filled the companion void left behind, and he ran with it because it made him forget the pain he felt because of the loss of his wife. Basically, he was rebounding.
Nothing against the FL and ML BUT let me get this straight the dad fell in love with his late wife’s sister??? Didn’t his wife just die??? How do people move on so quickly especially after a death mmhhhhnn