I may be wrong, but I believe Castro stripped those that left of their citizenship so they couldn’t come back. Didn’t want non commies to come back and start a revolution against him.
IIRC he did the same thing with the Marial (SP?) Boat Lift so they couldn’t be returned. Convenient way to have us take his criminals and mental cases.
A possibility, yes.
If true, his father would have been stateless until the time he naturalized in another country.