"Bridge Over Troubled Water" by S&G is something I could get behind. Nice suggestion, KingMikeJ!
These I think he could've pulled off and would've fit his style:
-"We Can Work It Out" by The Beatles
-"Surf's Up" by The Beach Boys
-"How" by John Lennon
-"The Scientist" or "Clocks" by Coldplay
-"Guiding Light" by Muse
-"Love of My Life", "Save Me" or "Somebody to Love" by Queen
(Yeah, most of them are kind of ballads or slow songs.)