Eh, with some serious gear revisions (as in: dop the packweight as low as possible) and some real pre-attempt training I don't see why it's not a possibility. Very much a challenge, yes, but hopefully he has a better idea of the scope of that challenge by now.
Starting the attempt this coming January, though... I don't know about that. First of all, he'll need a few months to fully heal this hip problem, and then he'll need at least several more months to get into serious condition for the trip, and there's always the unpredictable factor of training injuries. On top of that, I really do think he'd be better off considering switching up the trip timing, maybe jumping from section to section of the various trails in order to spend less time in deep snow. Trying for all four trails in 365 days is crazy enough as it is; hiking a large portion of them in the most challenging conditions the year offers doesn't make much sense to me when trying to be the "first" to achieve a feat. Once it's been established that it can be done, then it makes sense to up the ante with things like intentional bad-weather timing.