Divorced fathers rights to his kids when mother is out working and leaving

[Kazzled]

kids with random people? This is the deal, my partner and his wife split 4 years ago, and the daughter he raised full-time was taken from him. She then announced she was pregnant with his son, and then he didnt get any visitation rights with him until 6 months old. Basically now, this woman has elected to become a midwife and she works odd hours which requires her to be away from the kid alot! Currently she is living with her father and shares a room with the kids (they are currently 7 and 4). She gets her step-mum to babysit them all the time, to take them to school in the mornings and his son to kinder. His son only attends kinder 3 days a week and the other days if his mum is working hes spending time with this step mother. Is it legal for my hubby to request her work shedule (and her actually be made to give it) so that he can establish how much time they are staying away from her? We have asked her for it but she says outside of our time its none of our business. We're fed up with the fact we get only
4 days a month- more on holidays (lucky us.. she graces us with an extra 7 days..) while everyone else sees them more than her father and their extended family (we also have 2 children together now). Do you think we'd have a shot in court getting custordy of them?
Its not just her grandparents she'll leave them with though, its also aunts and uncles. What i am upset about is that the "grandparents" get more visitation than there own father does! P.S there is no custordy agreement in order and we have never gone to court about this as we have tried to play fair, but its slowly getting rediculous.