I am a bit in the same shoes as you, DH's family is very 'superficial' in their relationship. We've had to take DD out of childminder because she came home with an unexplained burn (don't get me started...) and have no childcare arrangements as DD is autistic and has severe speech and language delay so we have struggled to find something.
DH's mum lives alone, is retired, drives, and is only 1.5 hours away. When he told her the situation we were in all he got was a 'oh that's terrible'. So, my mum, who is brilliant, is flying in to day FROM PORTUGAL to help look after our daughter temporarily as we struggle to put some sort of childcare in place.
In my experience, you could say something but it wouldn't make much difference. It is how it is and if they are already not visiting you much they have chosen to maintain an arms length relationship, as have my DH's family, and i'm not sure a lot would change that. It's sad but at least you child has two wonderful nana's and you can count on someone for help.
Good luck with everything - I don't know much about refusing to go to school but it sounds very stressful, hugs xx