I'm asking this here because I'm very concerned about my 16 year old
male cousin.

Over the past few years, he's gotten in a lot of trouble at school. It
seems he started acting up when my uncle married his mom. He tries to
act like a "hot shot" and tries to be the center of attention as well
as a know it all. He was the center of his mom's world until she got
married, had another kid, and they moved in with my uncle's parents.
He's gotten kicked out of school about three times and has had to go to
court. No one in the family trusts him anymore as everything that comes
out of his mouth is a lie. He picks on his two year old brother and has
even pushed him on the floor causing him to cry. His mom has decided to
send him to some sort of boot camp program that is ran by the U.S.
Marines. If he successfully completes the program then he gets his GED
and help getting a job. He also has the option to join the Marines if
his mom signs a release form as he is a minor. If he fails the program,
he'll probably be sent to a juvenile detention center until he's 18.

It's been my opinion all along that he has some sort of psychological
problem that boot camp will not fix. I was recently made aware by our
grandmother who lives with them, that he acts like a baby sometimes. He
will suck on his little brother's bottles, watch children's shows such
as Blue's Clues while sitting on the child couch which is designed for
a toddler. He plays with his brother's toys and will sort of "snuggle"
up to his mother. He's like all over her and wants her to cuddle and
coddle him. I've never seen any of this but it is obvious that he's too
attached to his mom.
He's not violent and doesn't get very angry, he's intelligent but also
does stupid things. He doesn't use drugs as proven by a court ordered
drug test after he was caught with marijuana. He did steal his mom's
gun and no one knows what he was going to do with it. He ran away from
home once or twice but since they live in the middle of nowhere all he
did was hang out in the woods behind their house for a day or two. When
he goes out in public, he dresses like a "bad boy" as if he's really
trying to impress someone. He's very good looking and I bet most girls
would fall over him while dressed like that. He's always fixing his
hair even when he's at home or he's always primping as our grandmother
says. He's charming and can con anyone into anything. He comes off as
an immature teenager or kid rather than adult. Most people view him as
a 13 year old which is the age when he started acting up.

Something is obviously wrong. His mom is open to suggestions and isn't
afraid to hear other's opinions about her son. She says he's seen a
counselor (I think it was a school counselor) which didn't do any good.
Because of that, she sees no point in taking him to a psychiatrist. I
think he needs some professional counseling as well as perhaps some
medication like Prozac or Zoloft. I think if he doesn't get this help
soon then he's really gonna get screwed up.

What do you all suggest? What is your opinions on this matter? This
behavior of acting like a baby is definitely not normal for a teenage
boy. Something is definitely wrong, but what? Ideas, anyone?