Well, well, well... I always feel it is a delicate subject to go and suggest to go med-free. Personally, I have been blessed with the luck of being able to be med-free most of the time I had to bear with this disease (14 years and counting). On that amount of time, I took medication at diagnosis (during 3 months or about while I was battling to just survived and medication caused me more than my share of side effect nearly killing me...) and for a year and a half(recently) due to the formation of fistula, hence, first recognizable flare since my colectomy in 1999. So yeah, I took the humira (which stopped working) until last surgery (a year ago) and since, with a great discussion with my physician, I stopped taking it afterwards.
It is always a risk to drop a anti-tnf as it is kinda increasing the probability of building anti-anti-tnf antibodies and therefore trigger a higher response of the immune system once the medication is reintroduced (if need is). So more chances of reactions and more chances for a treatment failure. So on this aspect it may worth talking to the GI and see if it is or not a good idea as far as this goes. For instance, I had trouble with antibodies, Humira had not only stop working for me but I was having major side effects from that too. At that point, it is a matter of weighing the good and wrong out of this whole thing. And I can completely understand the desire of your son wanting to go drug free and living life like everyone around. It's worth considering it.
My other point is; was he responding to AZA? he could possibly go back on that in case of another flare. Remicade could be an option too and others medication might be available in due time.
Also, I don't know what behavior had his disease, I know mine act up severely when it does but remain dormant for long periods... This is why I allow myself to do things this way. It might not be advisable for someone else.
I hope it helps a bit...
~J~