My DH has an aggressive and toxic family who had had several internal rifts before I met him. He has a particularly weird and abusive brother who leads a very frightening/illegal lifestyle. His Ex never liked or saw this brother while they were together and as a pair they never saw brother and his wife at all. Upshot is he has been NC with his brother for over a decade and also sporadically with his parents who have crumbled under the pressure of the brother's exploits, and are not very nice people anyway.
Fast forward to now and DH has been married to me for five years, after splitting up with his ex ten years ago. They have two children in their older teens who have found it hard over the years as their mum will not cooperate with our household at all and has encouraged her kids to look badly on us (though they do visit and we have a very close relationship).
In recent years DH's crazy brother has tried to get in touch with DH's kids independently. DH was frightened by this and tried to stop it, but now it seems that his ex has struck up a very cosy relationship with the crazy brother and his wife, and is facilitating the kids seeing them/staying in touch, and from what the kids say it sounds like they all get together and slag off my DH. This process seems not only weird (i.e. why would his Ex, after so long, want to be in touch with this horrible relative of DH's who sets such a bad example to their children?) but also manipulative (i.e. the Ex and DB are trying to, all of a sudden, make a close-knit family involving the kids that excludes my DH.
I realise this is quite niche but does anyone have any experience? It is hurtful to my DH, who is a lovely man, and also to the kids who are going to fall in with the wrong crowd. Also why on earth would a long-divorced woman want to get back in touch with the worst member of an ex's family? Why try purposefully to cut DH out?