I do have a question...is your son done growing? At 6'5" he could grow out of the TE job. At only 15 I would think he would be better off playing DL and adding 50 lbs of muscle...just a thought...maybe I'm crazy. I see a lot of kids commit to a sport or position and then their body changes and they are out because they always wanted to play x.
Even in D1 a ton of kids change positions and it is happening in the NFL more and more.
The best camp my kid ever went to was speed camp. If I had it to do over again I would have sent to him to more speed and lifting camps and then see where he was at 16. But hind site is worth a lot