Advice re benefits and separation

[TheVirgin]

Hello, not sure if this is the best place to post this but need some advice. Long story short, found out about affair last year and divorce is well under way. We have two DC, 5 and 7. Decree nisi has been granted and I moved out of the marital home last week into another property mortgaged by STBXH while we are working out financial matters. He is paying the mortgage and I am paying the bills. I was a SAHM and he was a high earner (>£200k). Now he claims he cannot find work and has been unemployed since last year and I have to figure out how to pay my bills. It gets complicated though because he used me as an 'employee' of his company to get tax relief even though I never did any actual work for the company. I was also a 25% shareholder. So in theory I have received high income for the past few years even though he managed all of the money and I never got any of the income. My solicitor advised that I claim child benefit and child tax credits but I've used the calculator online and it says that I'm not entitled to any. Does anyone know if they will take my situation into consideration even though it shows that I have previously received a high income. He gave me my P45 a couple of weeks ago. Would he get into trouble with HMRC if they are made aware? I am living off a small sum granted after the death of a parent at the moment and not sure how much longer we can support ourselves. I am in the process of registering to become a childminder but it can take a few more months and a friends has suggested that I sign on for JSA while I am unemployed. I don't understand the benefit system as we both moved to the UK in our 20s and have never used it for anything or ever even claimed child benefit before. Thanks for any help or advice.