Benefit Cap Impacting Ukrainian family- Young Carer

Hi, I have been referred a case from local authority for Benefits Advice. 20 year old of Ukrainian nationality- refugee status and recourse to Public Funds. He is the carer for his five siblings aged from 3-14 as Father is in prison and mother is not present.
UC is significantly reduced due to both Benefit Cap and 2 child limit.
Advised him to get Fit Note from GP to start WCA progress.
We are looking to apply for PIP for him and DLA for the children, all are impacted by the trauma of what they experienced prior to fleeing Ukraine- this would also remove the Benefit Cap. 
I am struggling to find anything else that could assist - any advice or comments appreciated.

Many Thanks

It doesn’t help while they’re capped but I think it’s possible they meet the exemption to the 2 child limit: They or other children in your household are not your child or stepchild and you look after them under an arrangement with Social Services (except for formal foster care). Presumably social services were involved when Dad was arrested etc. Depending of the level of benefit cap, might be worth exploring a) DHP for rent shortfall due to cap (even if it’s paid directly) and b) whether social services would help them financially while things stabilise given their overall vulnerable circumstance.