42 years ago as a first-time mum, I sometimes felt annoyed that my own parents seemed not to want to be too involved with my DD, even to the extent of not even making me a cup of tea when they visited. Their attitude, I soon learnt, was that the baby was my job, not theirs, and reading MooMoo22's post I now see that was far easier for me to handle than the situation she finds herself in. As my kids got older they were great with them, I could trust them implicitly. They did school pick-ups, visits to the park, we joined some holidays together. My MIL WOULD have been more involved given the chance, but she didn't live close enough. Even so, she and FIL could be counted on to have the children occasionally. Looking back it was perfect all round.
Sadly I have no real advice to offer MooMoo2 other than that she must stick to her guns with a child at this young age. Like many grandparents I would have liked to have been more involved with my DGKs but I respected my DD's wishes. The GKs are approaching their teens now and we all have a great relationship. Yes, I had to get used to some "rules" that my DD laid down, but that was her and her husband's right. I understand that HIS parents get rather more leeway than us but they live closer and "get away" with things such as giving sweets.
I am very sure, however, that the MIL has serious issues that she needs to address. Whilst I feel very sorry for her, seemingly finding it against her nature to take a back seat, MooMoo22 must not take any risk where her baby is concerned. If this causes a rift with MIL, then so be it. Maybe then the rest of the family will seek to get her help - it simply isn't MooMoo22's job to do that. Clearly MM22 is a very kind lady, but her priority is not MIL right now.
Much love xxxxx