Yes - those things are closely related to some of the diagnostic criteria used by some of the tests for depression. The remission of those symptoms is a quite a good signal all by itself.

See for example https://www.medscape.com/answers/286759-14692/what-are-the-d...

And consider “ Diminished interest or loss of pleasure in almost all activities (anhedonia) “

— his ability to enjoy guitar for its own sake is a great sign.

And “ Sleep disturbance (insomnia or hypersomnia) “

…he addresses that directly.

But the presence of those symptoms doesn’t by itself mean that a major depressive episode is the best or only diagnosis.

But having some of those symptoms is enough to indicate you should talk to a medical professional, as they are very troubling symptoms.