Now that the children have grown up, ie safeguarding children is no longer an issue, if the police have offered to prosecute and she has refused, they can't pursue it.
Callistemon21 I to had lovely support from Ds and DiL (abusive ex is not Ds's father). but it is often a lonely and scary road to go down to call them out. Its recent so is still an issue and I am afraid of him still, tho managed the divorce under the new rules....and if you loved them "despite" you have to face grief and loss
and our O/P niece may be afraid of many things including being alone, yes, despite all..
I agree with others kittylester if you are not well yourself do what you can but sadly sometimes that is all we can do x
but downtoearth you poor soul to have to live with that so long.