This is claimed by Robert A. Goerman, I certainly don't know.
http://windmill-slayer.tripod.com/aliascarlosallende/
https://www.de173.com/alias-carlos-allende/
'Nine months later, as I write these words, I am reflecting on the many interactions I have had since then with the Allen family. Stepmother, father, brothers and aunt all have been honest and open with me. They have provided documents, correspondence, memories and every possible assistance. But they have asked me to protect their privacy, which is why, when I use their names at all, I do not use their real ones.
“We’re trusting you, Bob,” Harold said. “Don’t make us the target of kooks — or reporters either. I’ll help all I can, but hide my real first name and location. All the publicity could ruin my business.”
The conclusion of the “mystery” is not particularly pleasant. I get no great satisfaction out of revealing that the truth is — in a word — pathetic.
“Were Carlos Allende and his correspondents representatives of an extraterrestrial power which took root on Earth centuries ago and has long since established an advanced underground subculture?” Brad Steiger and Joan Whitenour ask in their New UFO Breakthrough: The Allende Letters (Award Books, 1968). They go on to state, “We do know that an investigator checked out Allende’s Pennsylvania address and found only a vacant farmhouse.”
But William L. Moore, who actually found the elusive Carlos Allende, says in his Philadelphia Experiment, “Although maintaining contact with the man who calls himself Carlos Allende has produced voluminous correspondence, several lengthy telephone conversations and a couple of face-to-face meetings, it is still virtually impossible to say very much about him with any degree of certainty.” Moore devotes an entire chapter and much of the rest of his book to the question, “Just who is Allende really?”
Spaceman? Gypsy? Product of “spontaneous generation?”
Nope. But don’t look in any of the sensational books for the answer. You’ll never find it there because Carlos loves to play games with those foolish enough to play audience.
The prosaic truth, as his family revealed it to me, is as follows:
He was born Carl Meredith Allen at 6:30 a.m. on May 31, 1925, in a house on the corner of Porter and Rosslyn in Springdale, Pennsylvania, the eldest of five children (Frank, Sarah, Donald, Randolph) of an English father and a mother who is part French. Neither parent has any Gypsy blood, despite the eldest son’s claims.'