A bit of background first, and I'll try my best to give all the relevant information, but as I don't know much about the workings of the system I'm unsure what I need to include.
My partner split with his wife 3 years ago after 13 years together and 7 years of marriage. They have an 11 year old child together. Their marriage ended very acrimoniously after a series of infidelities on her part.
When they separated he immediately moved out of the family home with just his personal belongings and stayed with his parents until he could find a rental place. Since leaving he has paid her child maintenance by private agreement on a weekly basis.
She has today received a letter from HRMC saying she needs to repay tens of thousands of pounds in overpaid tax credits. The tax credits were paid to her during the time that he had left the family home. (He's always worked full time. When he left she went on to benefits. She hasn't worked in 13 years apparently).
The notice says that if she claimed as a couple then both parties must repay, so she called him today and said he's liable for half. His answer was... but how can I be? I have receipts for rent paid to my own house. I didn't benefit from this overpayment so why should I pay half back?
We're both so confused. What does he do now? I've told him to call HRMC but he's still smarting from the phone call from his ex wife. We're these benefits claimed fraudulently? And is he liable to repay half as she insists?
Thank you for any help or advice.