AIBU to worry CMS deductions could push my son into crisis?

[Wokeuptired]

My son split from his ex almost 2 years ago, they have 2 children together and 1 child that my son brought up as his own, their was lots of drama in the relationship and his ex was very demanding, my son paid her maintenence every month and paid for other things for her like the sky bill and some h/p goods, at the end of last year my son took a very serious attempt at taking his own life and he got sectioned, he obviously couldn't work but his ex was still demanding money from him, In March he got his old job back but he had to save for a deposit and furniture as well as pay for prescriptions food fuel to get to work, he was around £200 short each month and we helped him out with that, during this time his ex refused to let him see the children and he has not seen them since January, he had an upcoming court case to get to see them, as the eldest isn't his biologically he had to get a lawyer to help him as he wants her included.
Now the CMS are involved and they have taken £1700 out of his wages this is £700 for the month and £1000 in back pay as they calculated this from December last year, this leaves my son with around £500 after tax, he can't live on £500 as he can't even cover his rent with that, he has just got himself sorted financially but still owes money.
He doesn't know what he can do as he has phoned CMS and they said it has to be that amount and he explained the situation.
He has been to his boss to see what can be done and if he leaves this job he will break his contract with them and they won't employ him again, he can't go part time and then do work on the side to make the money up.
He just can't afford to work, it's ridiculous as he doesn't want to go on benefits as he also pointed out that it won't help his mental health.
What can he do?
I'm just so worried that he is going to try and end his life again as this seems like a no win situation.

It does imo. If she’s just expecting the father to fork out for their children, that is such double standards. The OP’s son doesn’t sound very well at all either, sounds like a vulnerable adult. That doesn’t mean he should shirk his responsibilities, but I’m tired of the men bashing on Mumsnet tbh. I’m female before anyone asks.

@Whatalunatic Hang on... so the father has a legal and moral obligation to support his child, but the mother doesn't?
@RowsOfFlowers Absolutely this. Both parents should take financial responsibility, not just the father!

If mothers felt no obligation to support their children, the world would be absolutely fucked. Is there a part of that that you don't understand?

@bigboykitty I agree. Both mothers and fathers should financially support any offspring.

Why do you think that ? What entitles mum to expect the non resident parent to work to support his kids while she claims benefits instead of working ? Of course fathers should support their children but that applies just as much to the mother too.

@ThreadGuardDog Quite. Although some people appear to believe that once a woman is pregnant she is for some reason entitled to give up work (or continue not to work) and expect others to provide for her own child?
Of course a bio father has a moral and legal duty to financially provide for any child he creates.
So why is the same not true for a bio mother?

Nope. What the mother does - or doesn't - do is not the point here. I love the indignation - women everywhere working themselves into the ground to allow men to pay 10% of their income to supposedly support a child and just moan about it. Beyond ridiculous.

@Whatalunatic So you think it is acceptable for mum not to work at all, and to rely on solely on benefits and child maintenance to be able to financially support her own child?
Double standards much.