Yeah, but a new one is outside his budget unless he can find one used. Which considering it hasn’t had really any time in the market, I wouldn’t hold my breath for a while.
Basically, if you love Traktor, get an S4 mk2 if you need a new controller now and want to stick with 4 decks. (Dj Tech tools does a great deal of an S4 mk2 with free Chromacaps, a “Nice-to-Have” addition to a controller) Otherwise, you’ll be hard pressed to find a true 4 deck controller for Serato for less than 700.
I can think of a few off the top of my head, but a lot of them are old and discontinued, out of that 700 price point, (Assuming you’re using USD) or almost look like a toy and will probably leave you wanting more.