Chrissy,
This is dangerous territory as you well know. I wont say it is irresponsible to support his/her quest but I would stop short at acquiring them for him.
Personally, if it went wrong I could not live with myself knowing I supported this approach.
The need for medical support is paramount and I would make that absolutely clear. If he isnt ready to accept that then he cant be even remotely ready for transition and like it or not, that is exactly what this is.
Good luck girl.
Kimberley
