Well, I've recomended Haro in another thread, so I'll recomend it again in this thread! Haro makes awesome bikes, and if your friend is 5'9 then any of the Haro bikes (or just about any other brands of bikes) should do fine. And if he's on a $350 budget, then Haro is also perfect. Their top of the line bikes are between $350 and $450, so there's lots of options to pick from. Now I said top of the line, and those are the most expensive bikes Haro makes for BMX, so there is many other models they make for under $350. My bike was $230, and it's a really good bike. And if Haro doesn't interest you then there is many more brands out there that have very good bikes also, some of them for under $350 also. But I ride Haro, so Haro bikes are my area, you'll have to wait for other posts inorder to find out about other brands. I hope my suggestion is helpful!
PS: Haro's website is: harobikes.com . I'm sorry I forgot to include it earlier!