my point is the embassy may tell him (when and if they go there) you are looking for him and he may be able to give permission. So be sure you provide all your info
E mail the embassy. This way they will have your e mail address. (Also provide your full name. )
This is what i did looking for my friend. They told me the same info. Need his permission. A few weeks later he e mailed me directly. So apparently the embassy passed on the info.
Maybe they will do the same for you, or maybe he can give them permission if they do speak to him.
My friend had a life sentence. After 9-11 years he was sent back to the usa. (He was free when I talked to him)