confused with pisces ex

Broke up with my pisces 4 months ago and he still tries to talk to my best friend but will just talk about something random like a game or send a tiktok. I told my best friend to just talk to him back and its just going as if they are still cool and friends despite the messy breakup that we had. They will message for a day and then a week later he will message again. There is no mention of me when they talk why is that? Is he just wanting to stay friends with her or is he trying to do something else? I think he is still trying to consider me an option again and then suddenly stop when he finds someone else. But it could just be nothing and he is just bored but i don’t know much about pisces so i’m not sure if he’s just too scared to reach out to me.

p.s he definitely does not have a crush on my best friend