How do I tell corporate, you're making a poor choice in leadership?

I like the guy as a human.
As a leader, he is absolute shit.
He is whiny and needy and in no way prepared to be taking on a management role.
I think, in fact, it would entirely ruin him.
Problem is, they don’t have a viable alternative within the company,
Do I write corp mgmt and ask them to look outside for a better candidate?