Would this be enough for failure to adapt discharge?

Im sure there is more to story than you are being told. Discipline usually does not start at LOR. It starts at verbal, Letter of Counseling, Letter of Reprimand.

He has demonstrated a continuous pattern of misconduct. His attitude while being counseled or reprimanded will also have a lot to do with the outcome.

It definitely sounds like he has not matured enough, or self disciplined enough to continue his Military career.

Three LORs show a serious pattern of misconduct. If he got them all just while he was at tech school, you can be sure that he's on his way out. Sunglasses in formation, tripping a fellow trainee, and harassing a female? Sounds like he still wants to be big man on the block. He's getting his wish.

3 LORs would be merit for a discharge. The things you have mentioned he has done would be a failure to adapt to military lifestyle. The things he has done is not the way the members in the military conduct themselves. Don't get me wrong in tech school a lot of military discipline is thrown out the window but to get 3 LORs means its gone way pass the line.

Sounds like this kid is a ridiculous piece and the military is doing a good thing by getting rid of him. He needs to grow up.. unfortunately, this discharge will follow him and he is going to have a hard life in the civilian world...

He is showing that he cannot act maturely and his behavior is detrimental to everyone around him! Imagine being in combat with someone who wants to trip you everywhere you go.... gosh, how did he make it this far?