The father of the late Charlie Harper and his brother Alan was Frank Harper. He either died of food poisoning or was driven to suicide by his wife, the domineering Evelyn. (That's all established in the series 'Two And A Half Men'.)
From this point on, it's all conjecture on the part of Toobworld Central.....
Frank had a brother after whom Charlie was named. Uncle Charlie Harper was a low-life thief, known mostly for stealing furs. He would switch their inner linings and lose the labels before shipping them back East to be re-sold by an unknown partner.
But in 1956, he stole a crystal mink stole from a Mrs. Wilson while she was in Las Vegas. Needing some cash quickly, Charlie set up an elaborate scheme to sell it cheap for 400 dollars to Paula Hudson. (Her husband's family may have founded Hudson University in New York many generations before.)
When there was too much scrutiny on his cohorts once the police got involved, Charlie Harper tried to buy the fur back from Mrs. Hudson, even offering her a profit of 200 dollars. Finally, he had to resort to stealing it - which got him arrested once he tried to sneak it back to its original owner.
So Uncle Charlie most likely wouldn't have been around to serve as the godfather at his namesake's baptism in 1965.... Hard to be a role model from behind bars.
Although it wasn't brought up in the episode, Uncle Charlie was married and had an infant son of his own back in 1956. But when he got arrested and his wife found out about his "relationship" with a hairdresser named Lucille, she divorced him once he was sent off to jail. She later met a man named Saltzman who married her and adopted her young son. Charlie Harper's son grew up better known as Pepper Saltzman and became friends with Cameron Tucker and his husband Mitchell Pritchard.
So an episode of 'Alfred Hitchcock Presents' entitled "The Mink" can serve as a theoretical link between 'Two And A Half Men' and 'Modern Family' (with the added bonus of 'Law & Order', thanks to that Hudson University mention......)