Grandchildren

Your son might have issues with both mothers but surely he should be granted access/visitation rights, has he applied for this?
Then when he sees the children you can presumably see them as well.
Or is there a reason why your son has not been granted this?

Should you continue to attempt to get court ordered contact, you are setting yourself up to potentially have no future relationship at all.

Tread so very carefully.

Have the mothers said why they won’t see you? Have you been fighting your son’s corner instead of being neutral? (Hard I know!)

Generally, advice is to see the grandchildren on your own child’s time, but that is hard when they don’t have time.

As you’ve already done mediation, this might be impossible with one parent, but I would start trying to have a real and positive relationship with the parent in order to earn trust. Then possibly a relationship with the child would be possible.

A contentious relationship with the parents does not predict a future positive relationship with the grandchildren.

So are these two different women each with a child by your son and both are cutting you out because of his behaviour
Are they friends or is it just a coincidence that they ve bath cut you out at the same time ?
Monicas right grandparents have no special rights in Uk

If you live in the UK then there is no legal way of getting formal access to your grandchildren.

This is a predominantly British based forum, so if you could confirm which jurisdiction governs your case, there may be members who live under the same jurisdiction and can then help you.

No my son has his own issues/relationships with the mothers.

Can you not see your GC thru your son when he has the children?