This is no symptom of schizophrenia.

there's a book on the internet somewhere that says all schizophrenics are really hiding some sexual fantasy, that's what makes 'em schizophrenic. i also read, in the 'history of madness' by focault, that in the 19th century they believed that some madness, was the result of concentrating on one object, and being 'wrong', rationally, about the meaning of that object. this they described as 'monomania', and described as the most dangerous to society, becaues the patient seemed normal in every other respect, except when he was thinking about that one thing, which might make him depressed, or fly into rages. and one more thing, religious obsession and sexual intensity are also linked. turns out the more we are likely to think about religion, also the more likely to think about sex. as a sz person myself i speicalize in studying religion, i don't know if everybody's like that, but it is for me.
-onderdonk

found you an article...

Relationship and Sexual Problems Often Overlooked in Individuals with Psychosis -

[link removed]

If he was diagnosed - does he have any other kind of symptoms?