Family Allowance

Family allowance hasn't existed for a long time. It is now called child benefit. The person the children live with the most are the ones who can claim the child benefit. By doing this it allows them to claim other benefits like child tax credits and housing benefit if required.
Your son needs to apply to child benefit to get it transferred into his name. Two parents cannot both claim the benefit.

Child maintenance is not just about who needs the money, I think it has something to do with supporting one's children as a matter of principle.

I am pretty sure that those who say child benefit goes to the main carer are correct. He needs professional advice either from the departments concerned or from the CAB. It makes no difference whether it is the mother or the father claiming it is all about the children and who cares for them.

And maintenance is even more of a minefield.
DD had to pay it to DGC father as they were living with him, even though she was out of work at the time and his wage meant he didn't need the small amount they said she had to pay.
I don't know how your son would feel about this but just a heads up.

Sorry kathsue, missed your post!

What Kathsue said too.

What MOnica said! Or talk to the relevant department - they are not the enemy. Child benefit is not straight forward nowadays.

Citizen's Advice should be able to help you. Get your DS to make an appointment to see them.

Your son should get the child benefit for the three children living with him but he has to apply for it. The same with child tax credits but they depend on his income.
He can apply online or maybe just ring the relevant offices to get advice.
It might be advisable to get legal advice regarding the "supervised visits" and "suspicious circumstances".

Strep98, are you referring to child benefit or to child tax credits? Or both?

In my experience (although that’s not very up to date) it’s the parent with custody and prime responsibility for the children who should receive the money unless an agreement has been reached to the contrary. Might it just be a case of the payments still being made to the mother because your son hasn’t put in a claim for them?