I was getting a haircut today at my local barbershop when a guy came in who used to be a correspondent for CNN and had a pretty interesting story about Favre. As a correspondent, he covered the Superbowl in New Orleans, where he met Brett Favre. Over the years they became pretty close, and talked as recently as two months ago. The guy told me that not only did St. Louis call him up to ask if he'd be interested in playing, but three other teams contacted him too, offering him money similar to what he got in MN. Favre declined, saying he was 44 and not in football shape and was even having trouble remembering things.
Take it for what it's worth, but I see no reason to believe the guy I met was being purposely deceitful.