As he got twinkified, his brain got worse

I think his brain has always been that way Ig he just never expected his precious Crown Prince would grow up to be the way he is now since he always saw him as someone he needed to protect

No... I am pretty sure he just has an audience for his extreme himbo-ness whereas before we only got to see him in danger of seclusion where it couldn't truly shine. Now our guy gets to ramble to everyone and not just a tiny highness in the woods.