UC rent shortfall

Im writing on behalf of my daughter, she has been offered a new HA tenancy, there is a shortfall of 60 a month, she has PIP herself and two sons who have ASD and ADHD therfore entitled to a 3 bed need, is there any chance she would be entitled to the full rent due to the disabilities, also the younger boy does not sleep she is worken up several times a night and needs someone to stay on the bed setee several times a week to watch after her son?