If you read the article you would know that. Palmer is a highly respected QB coach that many credit with the development of Josh Allen. If you believe Kyler can improve and needs coaching, it makes sense to seek a QB coach, other than his dad, and given our connections to Carson Palmer it may make sense to see if his brother can help.
Most everyone agrees the problem Allen had was not his arm, it was his footwork. Most of us would agree some of Kylers issues are clearly footwork, throwing off his back foot, not stepping up etc. Palmer won't help him with running but he could help him throw on the run, or learn to move, reset and then throw.
I'm not saying he's the only good QB coach out there but it certainly makes sense to consider him. There are others, I think Steve Clarkson still does it, he tutored Hundley in HS and college and used to work with NFL QB's too. He played at SJSU I saw him play in college, he's been heralded for years. he's one of the QB coaches who told Logan Thomas you're not a QB you're a TE.