Need help picking a streaming integrated amp

ProAcs are great speakers. Which model does he have? I wouldn’t get an all-in-one solution — it’s a jack of all trades master of nothing, and your options are relatively limited. I’d get used separates to get him the best sound and value for the money. For $3k I’d get a Unison Unico 50 integrated (2 listed here now around $2k), an Avid Pellar phono preamp on US AudioMart ($500), and a Bluesound Node 2i streamer (around $400 used). The Unison amp is excellent and is a hybrid design that uses tubes in the input stage with solid state amplification, the Pellar is far better than any onboard phono pre you’ll get in a multifunction integrated, and the Node is serviceable for now but can be upgraded significantly down the road with a better DAC. If I really loved my nephew that’s what I’d get him, but if you don’t just go the integrated route. Best of luck.

he’s a tube kind of kid. the starting point is probably a tube integrated amp around 2k then build from there. 

In that price range, a Jolida or Rogue might be the ticket. Maybe a PrimaLuna.

As someone mentioned, the NAD 368 or 388 with BluOS works nicely and should fall between $1-2K depending on which you select (unless you can get a refurb, which you may be able to snag the 368 for under $1K).  I've got a NAD 368 + BluOS with PSB T1 and it works great.  I've used with Spotify, Tidal, Qobuz, as well as streaming from my PC.