The arts fuel the world, and the world fuels the arts
Without the arts, the world will shrivel, color drained away to the cool industrialization of coins and concrete. But money builds the roads, the walls, the buildings--upon which a mural can be adorned: a splash of creativity to gawk at during a morning commute, and perhaps fuel a half-smile before the drudgery of the day.
Innovation and investment build the recording studios, the mixing equipment, and nourish the people who will choose the next Hendrix to illuminate the soundproofed booths with their dreams.
Ambitions are circular, and to burn a candle at both ends may help one reach their goal that much quicker.
Art is a past-time, until it isn't.
But a corporate drone cannot live without pursuing art.
Someday, the two will meet.
In short, tell your friend to build other skills. A dream is only that, and dreams cannot pay the bills. A dream does not interfere with living. A dream may be realized, but one doesn't concentrate solely on the dream; sometimes it's even forgotten by morning. And when his youth is gone, he will need a fallback--even if that fallback is to support his drums. Success may come at 20, but if it comes at 50, he will be glad he spent thirty years building a successful life.
Live to your own beat, but make sure you can afford sticks, man.