I would think she has long left the building. She came in for some advice, as she is missing her GD, who she was obviously close to.🙄
The OP was brief - it just stated that her son, who is out of work, had missed a £50 child support payment, which he had paid, by now Mum wants another £100, and it's not clear if this is arrears or just an extra payment she wants. It's not clear how long her son has been unemployed.
Mum of child has retaliated by refusing to let the little girl see her Dad (and Gran).
Both parents need to step up to the mark - the child needs financial stability (of course), but she also needs to see her Dad and Gran, who both love her. As she's been staying weekends at Grans, there is obviously no risk to her.
This fall-out is about money.
Dad needs to find work asap, so that he can resume regular payments of £50 per week. If there's a delay or a reason he cannot work, then he, at least, needs to pay the statutory £7 per week from his benefits. The DWP will certainly be pushing him to find work (unless he is sick).
Mum needs to stop conflating child support payments with contact. They are two totally different things.
It's not said if mum works, but, again, if she's on benefits, the DWP will also be pushing her back to work, now that he little girl is at school. (Unless she's sick).
So, hopefully the money pressures might ease anyway.
The child - not mum, not dad, and not Gran, needs to be put first. She's 5, she won't understand any of all this.
The bedsit situation is irrelevant, many people can't afford better, especially, if they live anywhere near a pricey area.
The hyperbole about Dad being feckless and Gran being a molly-coddling enabler is pure supposition, thrown into the arena for unknown reasons.🙁
Perhaps, for now, and for the sake of the child, Gran, if she has the means, could gift/lend her son the money to pay these arrears, and get the visits back on track. That is what I'd do.
Then, whether it's £50 per week, or £7 per week, he needs to make payments regularly so that Mum can budget knowing what is due to arrive.
Mum needs to resist the urge to use the child as some sort of bargaining chip. It's not fair on a 5 year old.