He's sly as a fox and crazy as a loon
"Sly as a fox" is an idiom for someone who is cunning and experienced; someone who can get what they want by any means necessary (sneaky and underhanded included).
"Crazy as a loon" is an idiom for someone who acts completely goofy or acts like the Mad Hatter of Alice in Wonderland.
Both of these are presented by the wife as left-handed compliments about her husband.
These "not quite sure they were compliments" are typical of older married people who've learned to appreciate the uniqueness of their spouse.