Housing Benefit Overpayment

[Julietf]

Hi. I am after some advice please. In May 2012 my son was renting a property and was getting housing benefit. Then he moved in with me. I notified the council. They were again advised in the September by the DWP. The claim wasn't cancelled until the following year and by then he owed over £3k. I never knew that he was still getting the housing benefit paid into his account. He was/is an alcoholic so he just spent it (which he shouldn't have I know, but he did). He has never been able to pay it back so I have been paying it. At the moment I pay £4 per week. Every six months I get a income/expenditure form to fill in for him as I act on his behalf. They always agree to the payment amount but then forget to add it so I then get a final demand and have the contact them to remind them to add the payment plan. I know this may be controversial, but if I just let it go it court, would there be a chance it would be written off seeing as they took so long to process the change in circumstances? It just feels like their mistake has hung over me years. Thanks