In many ways, people tend to be smarter when they are younger despite the knowlege they accumulate as they grow older. That is because their minds are, physiologically, more active. As we get older, there are issues of blood flow to the brain, and nervous system deterioration. Our reactions slow down, our cognition is not as good, even our speech slows down. So, like us all, in his younger days, Frankie was more on top of things so he was able to come up with suggestions about the organizaion of the crime families, etc. Memory does not necessarily have to fade as one gets older, so Frankie is going to remember a heck of alot of what he had previously learned, read, etc.

His drinking from a hose, etc. was a function of his upbringing in the milieu of cultures that is NY: informaility, if you will. His NY domain required that he be phyisically aggressive, not necessarily wise. That domain also subsumed various threats, even to family members. When backed into a corner, Michael threatened Frankie's brother. Now, such a threat is not that difficult to perceive. He's not a buffoon; he's sinply a product of his culture and experience which, sometimes, sharply contrasts with others' cultures and experiences.