[Solved] Some advice for recently seperated dad

Hi There I'm looking for advice on behalf of my brother who has recently separated with his wife, i wont bore you with the details but she had relations outside of the marriage which resulted in child number 4. They have 3 children between them . Any how, my brother works full time and earns just over £13k and his outgoings pretty much match what's coming in with very little left... he now lives in a small room in a house share and survives on Jam sandwiches. Where in contrast she does not work, her house is paid for by housing benefit and she pays top up, which is £4500 in arrears. She receives child benefit, tax credits, disability living allowance for the two older children and carers allowance so all in all a little over £3500 per month.She has now made a claim for child maintenance and they have said she is entitled to £65per week. He has the children two afternoons a week and on the Saturday. All three children are in full time education. He is unable to have them over night as he lives in one room. I am struggling to understand a few things and any advice is much appreciated. : 1 - how on earth he can pay £65 per week ? This isn't about avoiding paying for his children but i cant understand how he will keep a roof over his head. He cant afford a bigger place to have the children overnight, coupled with work commitments . He isn't deemed to be a priority with the council for housing as a weekend dad, but unless he gets a bigger place he cant have them over night. Catch 22 2 - If he is having the children a % of the time, would he not also be entitled to a % of the benefits she is given for their DLA, Carer, child benefit, tax credit? from the info i have been given only one person can claim, as she has already done this she has to agree that he can claim one of the benefits. She is outright refusing saying he has never given her any money so she wont be giving any. Ive tried to explain that the money belongs to the children and its for their care, the children don't stop having special needs because they are with their dad on the Saturday. When he collects them he has no money to provide for them and no where to take them. All the advice i have been given so far just stacks in her favor, she has to agree, he has to give her more money...... Ive not had any experience in dealing with benefits before , i raise too children and work full time, this is starting to make me wonder if its better is i lived on benefits. Please someone restore my faith and tell me there is something he can do ???