He's 100% correct. Trump is further behind in polls than Romney was, and has WAY more baggage.
Mike Pence is respected by both the GOP establishment and Trump supporters. If Trump gave Pence his blessing, these 2 fighting factions would unite and still have one month to defeat Hilary. It could be done.
At this point, the choice is binary - You're voting for a Trump loss, or you're voting for a Pence win. If Trump is only about Trump, he'll ignore Hewitt's call. If Trump truly cares about stopping the evil Hillary, he has to hand it to Pence.