How to proceed with large rent arrears £12k

Rent Arrears

My tenant has been with me since 2015 and during 2016 he started to run into difficulties. He had accident (he works for himself), someone crashed into his van, kid sick and wife does not drive. Now he got into arrears and nearly paid it off but still the rents were not enough. By lockdown he was %C2£7k in arrears, now it is %C2£12k.
I have just sent him a email suggesting he gets in touch with the council for any help (he is not on any benefits) or citizens advice & debtline. He came back saying his accountant suggested some help before and he ended up paying it back. He also said he would look into paying back the debt this year!
I did suggest that he looks for cheaper accommodation as he has only paid the full amount once in the last 4 years.
Obviously with lockdown I have been sympathetic to my tenants but this one has had my sympathies far too long.
Is there anyone he could contact about this debt to help him & me?
I was thinking of giving him an amount to pay back this year (his rent with maybe %C2£3k off his debt) or he needs to look for other cheaper accommodation.
Any help and advice would be greatly appreciated on how I should proceed.