Often these rashes that come up when one gets hot and should sweat are GZMHGBT. With the swelling and the progression to a more extreme febrile state it sounds more like GZEYBYT, but the wobbly feeling in the legs and pain of the joints and shins then sounds like a YBJZT. If there are only findings on the R side, then I’d try YBJZT. If there is anything on the L cun, also then maybe GZEYBYT+BZ. Another possible alternative for a more deficient pattern could be GZJHQT, but I think he needs a bit more forceful opening of the surface offered by the first two formulas, and this a very likely followup (or possibly where this could progress to in a few years if untreated and he develops a yellow sweat pattern and eventually arthritis).