I really sympathise with you. We have a similar situation with my mother in law (MIL) who is a fully fledged narcissist and who is now made worse following her divorce with my FIL. Ironically that decision was her choosing because she wasn't getting the full attention she demands (again, narcissist). The situation has backfired spectacularly because she continues to find fault with the world everywhere she looks and constantly plays the victim. She hasn't met anyone else which presumably largely has to do with putting anyone decent off.
With regards to our children she complains endlessly that she is being deprived of seeing them, based on the fact that she isn't able to simply drop in without any notice or the fact that we don't drop all our plans when she announces she wants to visit. The end result is she rarely visits as when she does, the entire experience is exhausting because if she isn't 'hosted' - meaning everyone focuses on her, listening to her stories, centring the conversation around her, etc - she storms out.
The bit that still irritates me to no end is when she does visit, she loudly goes on about how proud she is of each grandchild, and how well we are doing as parents, and how beautiful the bond is as a grandparent. As she barely knows any of her grandchildren it grates on me, and when she makes similar comments on social media with photos including her, many a teeth are gritted.
Sorry if this is a bit off track, I realise it's different from your scenario. It's mainly to share the irony of having in-laws who make all the noises of wanting to be involved, but do the very opposite. It's exhausting but with the help of a couples therapist, my husband & I have been able to find a really good solution involving providing her with a list of all available dates in 3-month periods listing out all activities we've got planned, or times that would be great for her to visit. That way we've done everything to make her feel 'valued' and 'included' - but of course she doesn't respond to any of it, as it's all planned out and doesn't allow her to drop in whenever she wants.
In a nutshell my MIL doesn't help at all but will do everything to make it appear as if she's a dedicated grandparent - I suppose it could be worse from the many stories one hears