I agree Starcat,that you and his family members grieve separately/no contact basis, as from your first posting you continue your no contact boundary with also his family members in place.
And its nice to hear,that you bear him no animosity and also saw his good traits,
I have had to do this also recently- I sent no card of condolence,but that I grieved in my own way and on my own,didnt mean I didnt feel the loss ,because I did,as at one time I did love that particular person who I had 3 children to.
It is an awful disease
and I send you my best wishes