She cannt claim in laws property. she has rights only in your house. even new law comes she will get share in your house, you accuqired after after marriage only.
You can file a petition for divorce as she is not interested in coming back to you. and also for child visitation. as your son is grownup, you can talk to him about his Future, if he is comfortable with you then you can call him to canada, Court grant child wish not her demand.