IF Mum is not happy for whatever reason, then no, if they have time together with mum there then that is enough, mothers know their own children best. The time will come when it happens naturally. IT will probably be sooner if mother can trust the grandparents to look after the child as she wishes, it is odd I think that any grandparent would push for unsupervised access, sounds to me like there is something they would do that mum is not happy with. Learnt this the hard way, one set of grandparents would not listen to us when we asked that certain foods were avoided on medical grounds as advised by the doc, for example, son too small to say no, they also refused to clear up sheets of thin horticultural glass in their garden, which would have been dangerous had a child fallen on them, [yes we did move them ourselves, but it seemed to show a lack of concern for their safety], neither child wanted to go on their own, and it would hae had to be an overnight visit because of the distance, we didn't push them, eventually they got to an age where they were happy to go, but things were not good, they'd not worry about belting them up in the car, for example and did not put suncream on them, amnd we once got them back from a visit badly burned and feeling ill because of it, they were oof an age where they still needed help putting it on. They were not allowed to get food when they were hungry either, and got into trouble for helping themselves, they'd been brought up to be able to hae food when they were hungry, as the grandparents had late lunches and evening meals they did get hungry, they were growing. And also they had inflicted a lot of corporal punishment on their own children and saw nothing wrong with that
Not all grannies and grandads are kind and caring, and we cannot judge what is right for this mum and child