"Account temporarily disabled for further inspection"

[Rolig Loon 21,630]

That's spooky.  It sounds as if your friend may have tripped LL's Risk API, so they are temporarily freezing his account until they can figure out what's going on.  Your friend might want to read section 3 of the TOS to get a feel for some sorts of activity that could raise questions.

[Rolig Loon 21,630]

That's spooky.  It sounds as if your friend may have tripped LL's Risk API, so they are temporarily freezing his account until they can figure out what's going on.  Your friend might want to read section 3 of the TOS to get a feel for some sorts of activity that could raise questions.

[Nyll Bergbahn 1,050]

It undoubtedly means exactly what it says, your friend's account is suspended for some reason while Linden Lab investigates. The 'password or username is incorrect' part however is a red herring and I think the full message includes a telephone number to ring, which when you do, you are merely told to submit a ticket. This is what your friend should so, submit a ticket to Support to appeal the suspension. If unable to log in to the website, your friend should not try to login but just open the Support page and use the form to contact Support using just a valid email address.

Regarding an email from Linden Lab, your friend should ensure that the email address he/she provided at the outset is still valid and if so, check the spam folder just in case it ended up there.

[Lindal Kidd 11,433]

It is possible that the account was phished.  Then, while some cybercriminal had access to it, they did something seriously against the Terms of Service, and the account was suspended.  LL is investigating to see who did what.

Your friend should file a support ticket at once, to at least let them know that as far as HE knows, he did nothing amiss.