While he wasn’t drunk then, his brain probably was helped along by a lifetime of going to far into tipsy.
When George thinks his life is over because of his uncle, he lays into him for everything. And to be fair, were his uncle a more capable man, George wouldn’t have needed to take over the business.
Uncle Billy’s wife had died years earlier, if I recall correctly, and he never quite recovered from her loss. He used to walk around with strings tied around his finger because he was so forgetful. He would even forget what the string was for and would tie another string around another finger to help him remember what the first string was for! Uncle Bill redeemed himself at the end by rallying the town (along with Mary Hatch Bailey) to raise the money to cover the $8,000 he accidentally gave to Potter. That was a critical role, without which, this story would not have had a happy ending.
It’s true, I think, that Uncle Billy was so scatterbrain that the Bailey Brothers Building and Loan would have been closed or sold to Potter after his brother’s heart attack and death if George hadn’t taken over. He was instrumental in the “miracle” at the end, which is a nice touch and totally out of character for him. So even Uncle Billy redeemed himself and in the process saved his nephew and family, the building and loan and even the community spirit of Bedford Falls.
The story is wonderful in part because all the characters in the movie are so human and frail and flawed but often manage to overcome those challenges when it’s a matter of life or death — or prison and ruination and redemption in the case of George Bailey.
As you can tell, I do love this story. It’s inspirational for all of us trapped in our little worlds and too easily pressured into settling for disappointment and failure at critical moments in our lives.