Son has rejected me

Hello everyone, and thanks for 'listening'. My adult son, 33, has been depressed for quite some time. He was in a relationship which produced 2 lovely children but now I can see that he was never happy, spending a lot of time on the couch and not really involved in family etc. I could go on about this but it would take forever even though it is part of the problem, this is not the immediate problem. 2 years ago he was involved in drugs and his partner found out and kicked him out. We all (the family) tried to help him but he shut us out, again and again. Since then he has blamed us all for 'not helping him', has become a little volatile and will have nothing at all to do with me particularly, even to the point of not allowing me to see my beautfiul grandkids, as well as not allowed to have any contact with his ex partner. All this I know is ridiculous, and I have tried and tried to approach him, even to apologise for my 'crimes' as he sees them. All to no avail. He says I should see a counsellor to find out how to approach him. Although it seems to me he actually doesnt want to fix our relationship on the one hand but he does on the other. I thought someone out there may have some advice on another way to show him we all care and want to help him get through this. Of course, we have all tried many times to contact him, he is just rejecting us but I think he is crying out for help. I have tried making suggestions about visiting, doing something all together, helping him with the children when he has them, many other things. Sorry if this is disjointed, feel free to ask questions. And thank you.