Glad to hear you are riding him for free – the horse owner is getting a sweet deal of someone who is willing to do the boring (or overly exciting) job of bringing a horse back into work.
And I’m glad to hear that you will just keep riding him until June. Even then I don’t think you should buy him, even if he is still progressing well. I think you are making this decision with your heart and not your head. He does sound like a lovely horse, but his long term soundness is still a gamble and your own future sounds uncertain. Have a long hard think about what you’d do if he never came right.
I’d do a quick calculation about how much you’d spend on him over the next year – then commit to putting that in a separate savings account for a new horse.
Another thing to consider – you don’t actually know how he is to jump. He might have a terrible jump, or rush badly, or stop, or just have a jumping style that you don’t enjoy (kick ride vs forward ride). Again you probably won’t know that by June.
Other posters have bought up something that I didn’t put in my post but that is always in the back of my mind – that my horse may never fully recover or may reinjure. His chances of a full recovery are good according to my vet (who is a top surgeon) – the injury was mild, it was caught relatively quickly, his rehab has gone well (aside from the odd heart-in-mouth moment), scans are looking good etc etc.
But he may re-injure. He just might not heal right. I won’t know for months. And I’ll be holding my breath for years.
There is NO way I would choose to be going through this. I have my fingers crossed and I can afford to retire him and get another riding horse if worst comes to worst, but still . . .