Hello, I am a solicitor with 20 years experience. I will try to help you with this.
These sorts of claims are possible but there may be a time issue here. The usual time limit for bringing a personal injury action ( and that would include for mental ill health) is 3 years from the incidents causing the harm or if a minor at the time 3 years after becoming 18. There are exceptions to this rule but there is a real risk that the 3 year limit will apply to this possible case..
Time limitation periods are complex and there may be a way to get around it. Swift action however is required.
You describe a situation where vulnerable child has been put at risk. This could lead to a claim for compensation.
http://www.apil.org.uk/abuse-assault-lawyer This is a link to the assoociation of Personal Injury Lawyers and in particular it is the find a lawyer section for lawyers who specialise in representing people who have been the victims of abuse. If you follow this link you should be able to find lawyers who are experts in what is a specialist area and also who are hopefully local to you.
I am not sure why you have given me a poor rating and I would be grateful if you could amend that. If you would like any more information please just ask.