MoonFlower

I am writing for a friend. He has been the main artist and songwriter on many songs (with no other artists or songwriters). He was not the composer of these songs though. He posts his songs on his YouTube channel. For songs he sang on and wrote the lyrics for on unsigned labels, the following information is given by YouTube:

"Ads might appear on your video.

Copyrighted content was found in your video.

The claimant is allowing their content to be used in your YouTube video. However, ads might appear on it.

Viewing restrictions: None

Monetization: Can't monetize video ."

I have researched copyrights and it seems that yes, a label owns the sound recording (SR) copyright. However, the songwriter has copyright of the song as well and also "each copyright confers each owner with several exclusive rights."

So, should he contest these copyright claims on his songs? And then he can also monetize his songs on YouTube?

Thank you