How do others handle the lack of support over the loss of their adult son/daughter due to their offspring staying in a narcissistic marriage?

Often the son/daughter has no clue that their spouse is narcissistic (unless they have prior experience and are educated in narcissistic PD). The NPD spouse is very manipulative, fooling their partner that they met the perfect match and then over time whittling away their partner’s friends and family members while convincing their partner that those friends and family are the problem. And it’s difficult to see a once loving parent-offspring relationship turn into the parents being cruelly treated and then blamed for the cruelty. And then the son/daughter and their NPD spouse play the victims and victim blame while increasing the maltreatment and distancing of the parents and siblings because they voiced their dislike of how they’re being mistreated.

People who’ve lost a son/daughter, brother, sister, or grandchild because of death are allowed to share their grief and have support from others. They get extra support  on the birthdays, holidays, and dates related to the deceased. They can post about their loss, share memories and their continued times of missing their loved one. However, those who’ve lost their son/daughter, brother/sister, or grandchild who is still alive, yet no longer have contact because of their son’s/daughter’s narcissistic spouse have no such support. And they’re constantly reminded of how alone they are in their grief every time they see the outpouring of love and support for those with a deceased loved one. And due to social norms parents who lost their son/daughter due to the SIL/DIL’s narcissistic manipulation, controlling, scapegoating, gaslighting and other abusive behaviours are expected to keep silent about the abuse that led to the loss.

Do others share with Facebook friends their story of such loss due to NPD? Does a wider audience other than your closest friends and immediate family know that you lost a son/daughter/grandchild due to the NPD? Or do you keep silent in fear of being further blamed because the NPD has been trash taking you, making up lies in their scapegoating of you? Our NPD DIL has raged and lied so much that we won’t be alone with her and our son ever again. We no longer see our son and grandchildren, there’s no contact. We lost the son we knew, and will ever know our grandchildren, yet are alone in our grief, and no one says “so sorry for your loss” and no one shares good memories of him before he was forever changed and gone.

So, is there a grief support group for such parents and siblings? If not there should be. And I’m asking for something more than informative and supportive NPD Facebook groups (very helpful groups) because they’re not a good location for this needed support since the posts/comments can be seen by others like the NPD and their flying monkey enablers which then adds fuel to the fire.

Thanks for the help.