^^^That's really BAD advice(may even be illegal)..Ignore that.^^^
Yes, he should just accept some quacks diagnosis of "ADHD" and hide the rest of his life. Let's listen to the guy with the Dunce Hat.
"bad advice"? Oh the irony.
And NO, It's absolutely not illegal to keep that to yourself. Like others have said, MEPS will process you including a physical and mental eval.