I seriously feel for your nephew! My son's doc started him on Ritalin @ 1 tab per day, went to 2 tabs (one he had to go to the nurse at lunch for). Then he couldn't sleep so the doc gave him a downer to take at night, then the Ritalin lost it's oomph, added another tab! That's when I said "ENOUGH!"
Went back to my local family doc and did the diet strategy, no starches, red food dye, and sugars......and gave my son (Shadoe) a cup of coffee with creamer and honey (weird, huh) about 15 minutes before bedtime and he was out like a light.
He seemed to outgrow the ADD during puberty and no problems in High School, things just clicked.
I think the ADD is coming up because he's not in the class/studio environment he was in up in 'Frisco, where he'd be using multiple senses, ie, sight, touch, hearing, even smell. It's just him, his books, and his tablet in his own place now. (doing the required non-art stuff for the degree)
In the last week, the vaping, ie, nic seems to be chilling his mind out so his studying isn't misfiring in his brain. He hasn't changed his diet, exercise, or anything else, and he just takes a vape here and there. He's sold on it so far.
Have to tell you it was a relief because he had researched ADD and had mentioned he was thinking about picking up SMOKING for it!!!!

And that punk (ok, he's 6'1, so maybe not the right term, lol!) was the kid who got me to quit smoking in the first place! He may be a foot taller than me, but he still fears the wrath of the "mom from Hell"! It's a running joke, but I had my moments when he was being a nutty teenager.