Would that make Alex Cable's uncle and stepdad?
Honestly, even if I like Maddie I think that writers just bring the worst of her and Jean when they are on the same place. Jean and Maddie herself have enough toxic drama already.
I guess it depends on her intentions. If she is willing to help Krakoa she surely could be given a place there but if she comes back as an enemy to break havock I seriously doubt that. Characters like Sinister and Apocalypse are allowed because they are doing something for Krakoa and at the moment not causing trouble