Grandparent's rights to visitation

One of our son's came in and told us he was leaving our family business and this ripped our heart out. We also had to let people go from work and has left our famliy torn apart. The wife seems to be the one that answers all questions and cause of the heart ache she can't understand why we're upset. So do to not talking and trying to understand the reason for this change "What do you say?" We have keep their children from day 1 at the family business and in one day we didn't see our grandchildren for 2 weeks and was promissed from our son this would not happen. We have asked questions and even had a meeting with the son and his wife and most of the answeres were from her not him. My family was very close and we as parents tryed to stay out of their way and tryed to be there for them and help take care of the children and other needs. Our other son has also stuck his nose in this matter and he doesn't work with us but he is also trying to keep his son from us. I guess their trying to see how far they can go with this. I'm a grandmother that isn't going to sit by and do nothing so that's why I am asking questions before I confront them and show them I will not sit back and do nothing. Because we have done nothing wrong and it's seem to be coming back on us. The other grandmother and great grandmother on the daughter in laws side is keeping the children when not in school and that fine but the daughter in law said that she "thinks" her mother is doing drugs again and yet she is letting them stay with them? This women has been in and out of prison for drugs and so she would let them stay with these people knowing that and the grandmother and great grandmother and 3 other people live in the same house. I just need some kind of answers and direction to use.
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