Ours are open.  Son’s biological grandparents are involved in his life.   They consider both kids their grandchildren.   We went on a trip when daughter was 7 months old she house sat and watched both kids.  I trust both of them. Daughter’s biological mom is ok but rest of family scares me.  Son grandparents are thrilled they didn’t have to choose between raising him and him getting lost in the foster system.  Late August we struggled finding a sitter son’s grandmother offered to spend a few days at her sisters vacation home and watch the kids.