Can "as" be used as a relative pronoun ?
As | Definition of As at Dictionary.com:–pronoun
13. (used relatively) that; who; which (usually prec. by such or the same): I have the same trouble as you had.
No.Can "as" be used as a relative pronoun ?
Yes.Can "as" be used like a relative pronoun ?
As I later discovered, he was not my real father.
Note that, unlike 'which', which can also serve sententially, 'as' can be either anaphoric (i.e. following its referent) or cataphoric (preceding, as here), while 'which' is only ever anaphoric.
'As' can also function as a general (non-sentential) relative but normally only where its antecedent is a phrase either consisting of, or introduced by, 'such' or 'the same', e.g.
I have the same problem as you (have).
Such events as these (are) are difficult to predict.
'as' is not a relative pronoun in the English language. "End of debate."
Relative pronoun | Definition of Relative pronoun at Dictionary.com:
Jocular spirit? I never joke.