I have never heard of such a thing, and I suspect that it wouldn't work for very many people, if any. Unless his therapist is an M.D., I don't see where he or she gets off making such a recommendation. No wonder you are concerned. Considering the half-life of T, I should think that intervals of two weeks would be the outside limit for most guys, although I do know one guy who is pretty stable on a three-week interval. He's the only one I've ever heard of like that; everyone else I know who injects does it weekly, biweekly, or three times a month.
I wish I had some data or a scholarly journal to offer you, but I don't.