What can I do to remain part of my grandchildren's life?

thats too much for me to read...I'm weak from hunger right now, sorry. But I will give you this advice...Grandparents have no rights to a grandchild, until they establish them in a court...hire yourself an attorney so that you can have court ordered visiting time given to you. If your son is too weak to demand that his children know his family then ...you take matters into your own hands.