I have 2 sons, one lives permanently with me, the other in an alternate model that I have to sue first. At Mama, the two are not even allowed to talk to each other on the phone, she even checks call lists. Once she took his laptop away from him because the two of them had a video call during quarantine. I had to threaten her with a surrender lawsuit so that she would give it back
Mothers… Some are really sick.
Complement:
Since both children are - also - yours, there's no obstacle to contact with you. You will not have any influence in the area of your ex. But the two will form their own picture of their mother.
How old are they and what do you think of it?
Supplement 2
Do you want to change something on the interchangeable model?
With maternal behavior, this could not be without success.
How old is the son with the "difficult" mother.
In principle, children are allowed to choose their friends by the age of 14 at the latest, and parents are only allowed to limit contact if they can explain why the friend has a bad influence.
And there are very strict rules for this, a bad influence would be, for example, if the young person gets alcohol or cigarettes through his boyfriend, or if crimes were committed together.
And what applies to friends, of course, applies even more to half-siblings.
It becomes more difficult with under 14 year olds.
But since there are more than friends, every judge would not see it differently, even with a 10 year old.
I would bring the youth welfare office on board.
With what argument does she not want contact?