Nope - not too harsh at all, actually he's spot on.
From experience, that paragraph was probably drafted or edited by a lawyer. The giveaways - "whatever royalties exist, if any". Almost nobody says "if any" unless a lawyer told them to. When lawyers take depositions, or are in any situation involving direct examination, they aren't allowed to ask leading questions (only on cross-examination). So you can't ask "what were the royalties from this track", as an example, because the question leads - it assumes that there were royalties. So, a lawyer rephrases that to say "what, if any, royalties were earned from this track?". The giveaway is the "if any". It's legal-ese.
Secondly, a lawyer would have told the guy that damages might extend to the royalties from album sales - not just the individual track - which is why it's limited to this song; as well as the extended damages due from willful infringement, which it at least appears, he was just very very very careful not to admit, and perhaps to try and obfuscate. That's what it looks like, anyway.
"Not properly credited" - this is legal speak for "don't admit fault and say it wasn't licensed"...crediting wasn't the issue (obviously), the song and recording wasn't licensed at all. He's not 'fessing up...he's likely laying the ground work to try and settle for a pittance of what he is liable for, or to try and persuade a judge this wasn't willful infringement because it was some sort of "oversight".
IMHO, your friend needs a good lawyer, needs to make no representations or responses on Facebook or anywhere else in the public domain, certainly needs to not respond directly to the guy - definitely not, nor his lawyer - and needs to keep all his correspondence to his counsel from now on. He's probably got a winner, but it appears they're trying to trap him into the classic mistakes of either waiving his rights or diluting his own case.
