No, Alex Van Halen is NOT the most under-rated Rock drummer of all-time. That would be Earl Palmer. EVERYBODY knows AVH’s name, what band he’s in, what instrument he plays, and how "good" he is. In contrast, how many know John Bonham stole the intro in Zeppelin’s "Rock And Roll" from Palmers intro in Little Richard’s "Keep A Knockin’ (But You Can’t Come In)"?
How about D.J. Fontana? (who? ;-). Hal Blaine (Los Angeles studios, heard on about half the hits in the 1960’s including those of The Byrds, Simon & Garfunkle, The Mama & Papas, The Beach Boys, all the Phil Spector productions, and on and on), Bobby Graham (English studio drummer, heard on the early Kinks hits, and lots more). David Mattacks (Fairport Convention, Richard Thompson, dozens of others). Kenny Buttrey (Bob Dylan, Neil Young). Richie Hayward (Little Feat). Ronnie Tutt (Elvis Presley). David Kemper (Dylan, T Bone Burnett). Jim Gordon (Dave Mason, George Harrison, Derek & The Dominoes, Traffic). Do I really have to mention Jim Keltner (Ry Cooder---who schedules his recordings around Jim’s availability, Bill Frisell, Dylan, The Traveling Wilburys)?
If you want to do your son a huge favor, introduce him to the recordings of "working" drummers. If his goal is to get in a Rock Band, get a record deal, sell a ton of albums, make a fortune and buy a mansion and a Ferrari, and have a stripper/model girlfriend, well, good luck to him. If that plan does not come to fruition (as it very, Very, VERY rarely does), what’s he got? A giant drumset sitting in his bedroom (or your basement).
If he plays like Alex, or Bonham, or Peart, he is not gonna get the gig with the best songwriter in your town. Songwriters are looking for musical accompaniment, not show-boating (look how good I am!). If he moves to L.A. to "make it", he’s not going to be hired for recordings. Their style of playing is very limited---Rock. Have any of them were ever hired by a major artist for a recording date? Know why?
The number one complaint about drummers from other musicians, and songwriters and singers, is 1- their lack of musicality. Lots of drummers approach drumming as if it’s an athletic event, not an artistic expression; 2- they "over-play", Too busy, too loud, they don’t listen to the other players, the singer, or the arrangement.
If I had a son who wanted to become a real good Rock ’n’ Roll drummer, I’d buy him the first two The Band albums and have him learn all the drum parts (about half of which are played by pianist Richard Manuel, himself a musically great drummer). As he’s doing that, have him analyze not just the "how", but the "why". The wisdom learned by doing so will serve him well his entire life.
An old joke:
Q: What do you call an unemployed drummer?
A: A drummer.
badaboom.