I’m so sorry for your losses
Your horse is cute! Nice mover! And, I’m still sticking with stifles. In my experience, really typical for the breed and type. Good news is the right kind of work might just fix him up without injections, a holiday won’t make him worse as long as you keep in mind that when you start again, you need to be mindful of the type of work. A search on these forums will probably give you a TON of info on what works to strengthen the muscles supporting the stifle and which exercises should be avoided.
And that said, you might also have some gut issues going on as well. If there was upheaval in his life or feed changes or whatever due to the Camp Fire, I’d go ahead and treat - at very least a good probiotic, some alfalfa daily if available, and if you can get your vet to give you a 'script, Sucralfate. Some vets still downplay the havoc stress can play on guts, so you might have to give a little push. Hell, you could even try some of the OTC varieties available (search on this forum should reveal dosages, etc.). They are more of a pain in the arse to give because of frequency, but it you can get your BO to give it a whirl for a few days, you’ll either see a difference or not. If you do - then keep treating with vet involved to get the right drug for your horse’s particular situation.