A. Combo amps have no place in hard rock, at least not on bass.
B. The LH500 is a great, warm, "tubey" sounding amp, but it uses a fender tonestack. If this guy knows nothing about gear, he won't get a good sound out of it. Bass and Treble are boost only, Mid is cut only, therefore, the so-called "flat" setting is 2-10-2, or even 1-10-1. If the guy set all the tone knobs to 5, or in the middle, he'd have a horribly mid-scooped, bass boosted sound that might sound nice in his bedroom, but will result in nothing but mud and getting lost/buried in the band mix with guitars/drums, etc. It's not the amps fault....it's another case of RTFM......Read The F?#$&@! Manual, and again, not having to be a gearhead, but at least knowing how your gear works. Sounds to me like the guy is going to have to take an interest in his own craft to sound any better than he does now. Also, if he learns a little bit, he will get much better performance out of the gear he does have, rather than constantly buying new gear and thinking it sucks too, because he doesn't take the time/put in the effort to learn how to operate it.