Brother borrowed 20k without consent

Our father then in his 70's moved in with my brother for a while when our mum died & my brother unofficially took over his general financial affairs to ease dads stress. My father subsequently moved in with a new companion friend who owns her own home & is self sufficient with her own pensions & substantial savings so for the last 10years they have been sharing their modest bills & living expenses. They keep their finances separate & my brother has continued to manage my fathers shares & bank account. My dad had a £20,000 nestegg in shares & receives state pension & a small works pension which amounts in total to about £225 per week, he & his companion have little expenditure as they rarely go out except for food shopping & they belong to the local bowls club so dad does not use all his income & always had more than enough cash in his current account not to worry what he spent.

It seems my dad has just used his cash card & a credit card which is paid in full each month by direct debit, for the last three years dad has not had or seen a statement because my brother began doing all dads banking for him online & dad entrusted him with all his details. All dads relevant post goes to my brothers address as my brother dealt with it all supposedly to relieve dad of any mundane paperwork. Dad has never worried what his current account shows is available as there is always enough for what he needs & he trusted my brother completely.

Last week my dad told my brother he needed to withdraw £2,000 so if not enough in his current account if necessary he would just cash some of his shares but my brother informed dad that he hasnt got any money at all. Dad rang up about his shares and was told that the £20,000 he believed he still had was cashed in April 2011 & paid directly into his current account. On checking with his bank it seems this money in two lots of £10,000 were transferred into my brothers bank account soon after. Today my dad learnt he has only £50 in his current account & he knew nothing of any of these transactions.

When he confronted my brother he said he has no money hiself & had got into financial problems so borrowed the cash but cant remember exactly what for. He told dad that he had told him he was borrowing it in 2011 and that dad had said it was ok & gave him permission to do so. My now 80 year old dad (who incidentally has all his facalties) is very upset & feels totally betrayed as he no doubt would have lent my brother some money had he asked but clearly wouldnt have given every penny he owned. Dad says he did not agree to anything & certainly had no knowledge of closing his shares so it apears my brother signed for & arranged this fraudulently. My dad would help anyone out but everyone knows no matter how generous my father might be he would always want to know the ins & outs of any loan he agreed to so at the very least my brother would have had to have given him an explanation at the time - nobody just hands over £20,000 without good cause.

Dad put my brother in a position of trust & has been taken advantage of but it would seem he has no proof that he is owed this money. My brother has an expensive car & a house with a morgage & is expecting to be made redundant soon so may receive a payment from that. My brother has always given the impression he was doing ok and has always been held in high esteem by everyone so this is all very out of character, I myself would have entrusted him with anything before this so I am in total shock over it all.

Where does my father stand over this? He is worried sick as he cant even pay his share of his bills this month? I have told dad not to worry as I will help him but I know all this is making him very ill, he is devastated & lost. He thought he had a little nestegg to see him through his days without any worries but suddenly has not a penny to his name.

My brother has said he has no money so cannot pay him back and I know my dad will not want to take legal action against him even if he coulld but he would like him to at least sell his car & downgrade it to give dad some cash & maybe agree to sign even a modest repayment plan to give dad some peace of mind. Presuming my brother will agree to do this can anyone suggest a template agreement available on line he could use for this that would be legally binding.

Sorry if this is long winded but I would really appreciate some any help or advice please.
Many thanks for reading.