What to do with horse I can't afford

[Blackfellpony]

I have owned horse for 11 years. He has been on loan for the past 6 as I can't ride him for various reasons.

Loan home (riding centre) now can't keep him as they are closing down. He has been kept there for years as a companion to another pony and was used on the odd ride but hasn't done much. They kept him as he is a sweety and everyone loves him more than him being of any use.

I have found a retirement field for him near me but it's £100/pcm and I really really can't afford it. I can't find anywhere cheaper. I didn't know he would be coming back as he was on permenant loan and not meant to come back. I haven't even seen him for around a year other than a quick drive buy to say hello as he was so content.

He is 20 years old. He won't hack alone, hates schooling, won't travel in a horsebox or trailer without full sedation and is very hard to ride. He is very sharp, jumps like a stag and is highly unpredicatable. He spins and has bolted on more than one occasion and I would be scared to get on his back.
He is no good for showing,hunting, dressage or anything really if I'm honest.
He also runs along fence lines and ruins fields.

Loaning him is an option but am I likely to find someone again that would want a horse like this?

What are my other options. Euthanasia even though he is healthy and happy grazing with his friends?
Selling him but then he could end up anywhere?

Please be kind I didn't realise 11 years ago things would have changed so much financially

I think the bit that stood out for me in respect to this horse being kept as a companion is that he is a field trasher and runs up and down the fence line. It would stop me taking him on as a companion if I were looking, as a companion has to be chilled and happy to be last horse out if necessary.

op I haven't read the full thread but I saw a lot of support for putting him down early in the thread. I have to say I agree, pts for a relatively old horse who has no particular purpose and doesn't suit a 24hr outdoor lifestyle, isn't the worst thing that could happen to him. You've done your best for him over the years and now this is the best for you all longterm. As a pp said the British Horse Society offer support 'friends at the end' I think it's called. A tough decision to make but definitely the right one.