I know you’re trying to help but honestly just stop replying to him! He’s stated more than once that he thinks he’s a writing God - a literal quote - and that his work is far superior to that of anyone else. He made a thread that insulted his editor for editing his book.
So, as much as you’re trying to help, he’s not going to listen. Best to just leave him be and not reply at all, honestly!
As for your statement though, it’s incredibly true! I try to take all the feedback I get and take it to heart! Some are stylist choices that I sometimes change but most times don’t, but feedback about the plot and characters - and some grammatical errors and typos - are ALWAYS applied as long as I agree and/or more than one person has pointed it out.
Learning never stops in any aspect! In everything one does, there will always be room for improvement and we must be willing to learn!