When you record a song, your imperfections stand out. It's much different than playing live, where a flub or a mistake can just be glossed over, as long as the energy is there and the crowd is into it.
I myself am a HORRIBLE singer. People pay me to not sing. I'm not going to bash someone else's singing because of this. However, I think your singer would greatly benefit from taking singing lessons. If he's offended or uncomfortable, just let him know it's in the band's best interest for everyone to do whatever it takes to improve.
I comemend you for putting this out here. It takes guts to take your recordings public, and even more to straight up ask for criticism and advice. I hope you get some good advice from the TB community.
Well said. If all serious singers had a vocal coach , the world would be a better place, too.