My boyfriend's relation with his ex unsettles me

Hi there. Well something is bothering me and I don't know if it's ok for me to be upset or not. About a week ago, my boyfriends ex girlfriends grandmother died.

Her and him haven't really spoken for the last year or so. But she called him to let him know and for support.

I honestly didn't mind at first and felt sorry for her, but her and my boyfriend have been in daily contact since. It went from her talking about her grandmother to catching up on old times on their relationship.

She knows about me and our relationship, but from the things I've seen over the past week I feel like she's over stepping boundaries. What should I do ?