Sorry to hear about the circumstances all round, Patrick - sounds like an unwelcome situation for everybody.
I think the key point to make here is that you're in a legal situation so will need professional legal advice from which to make a decision on the matter.
Obviously, on the one hand, if the client has a contract to pay you for a full 12 months and this is not going to be honoured by your tenant, then there's a good chance they are in breach of contract and you in a position to claim the outstanding payments from his assets.
However, the fact that the guy is going through a divorce, not to mention is in rented accomodation, means that his actual assets for paying you may indeed be unavailable, leaving with you little point in pursuing action through the courts for payment.
I suspect that your solicitor will not simply advise on that count, but indeed if the specifics are as described, then you may find yourself encouraged to reach a settlement with the tenant where you are able to recover some monies, but not the full amount.
The resolution to this situation really does depend on the actual specifics, so a solicitor should be better placed to provide advice on this.
Hope that helps.
