I totally understand how you feel @Overthebow. My mum, who I am close to, was super enthusiastic about helping with my son (her ONLY grandchild) & was full of plans of how we could all spend days together & she would be no.1 babysitter & would be my back up for the times my husband had to work away (his job sometimes required that). Then, our son was born &.....hardly anything.
When he was newborn/young, she was fit & well, local to us & retired. Aside from the odd babysitting stint & daytime couple of hours of care at her house only (pretty inconvenient & impractical), that was it! Never any offers for more, clearly not keen, excuses galore, so I gave up asking in the end. Our son was not at all difficult or remotely tricky to look after.
There were so many occasions when I was on my knees with exhaustion (& occasionally genuinely ill with something debilitating) but she'd tell me to call my husband home from work (I didn't!) - never once offered to come & take our son for a bit.
No overnights, no days out, no birthday party help, no school run help, no 'come for tea at nanny's, etc etc...nothing.
It really affected my relationship with her at the time & it still niggles now.