never lend to family

Think it will be difficult to get the money back caz55 as it seems it was not in one loan but over a period of time. Try the High Court and Sheriff's office.
Not sure if I agree with giving rather than a loan as I think people should face up to their responsibilities and pay back money which has helped them out.

Oh dear, how sad.
I agree that a loan should really be viewed as a gift.
We've lent to different folks in the past, including DC, and most has been repaid eventually without our having to ask.
If you cannot "write off" the money and just accept (or indeed be able to afford) as a loss then you can easily take out County Court proceedings to recover the money. Presumably you know where he lives? Involving solicitors, IMHO, would be inflammatory-and unnecessarily expensive.

I agree about giving instead of lending although I realise it is not possible for some.
We have worked on the principle that they will get it when we die so would rather them have it at a time of need.
If I really needed it back I would set up a realistic repayment schedule and expect it to be kept.

Better to give than lend and, if you do lend, never lend more than you can afford to lose.

As far as legal recourse for repayment is concerned, I think you should consult a solicitor. If legal costs will be considerable – and they often are – you may be wiser to write off the whole experience, including your middle son if that's what you really want to do. Bear in mind also that just because there is a judgement that money should be repaid doesn't mean that it will actually happen.

How sad that you have this rift in the family - why did you lend him money if you did not get on with him?