That's a hard dollar figure. I suggest
Klipsch Quintet 5.0 satellites. Vanns often has them open box in their clearnce center for $225 or NIB for $250 shipped. Add $120 plus shipping (on sale) for an inexpensive
Dayton subwoofer. That combination with shipping will just about eat up your whole budget. The Quintets are some of the better inexpensive satellites, but like all satellites they have to crossover to the subwoofer a lot higher than I like. About 120hz for the 4 satellites and 150hz for the center. But they sound god for satellites and play a lot louder than most their size.
What I would rather see him do is invest in a pair of Behringer B2030P ($130/pr @ amazon) and a
better sub but that takes you $50 over budget not counting shipping. As money allows he could just add more pairs of Behringers to get up to 3.1 (and a spare), and then 5.1 plus a spare (3 pair total) as money allows. This system would rock in a medium sized room!
Good luck.