“He is wished to be here” is marginally grammatical, but in practise very unlikely.

Although he may be cast in the “object” case with an infinitival complement (I wish him to be here), it is not an actual object of the verb wish. It is actually the subject of the clause complementing wish, (I wish that he were here) and only formally an object, as it were “by position” or “by construction”. He doesn’t really sustain being cast as the subject of passive wish.

Moreover, wish is semantically oriented toward the Agent, the wishing person who is the subject of an active sentence: it designates the Agent's emotional state, and ordinarily has semantically very little (if any) actual impact on the eventuality which the agent desires. The subject of a passive clause is taken to represent the Patient of the verb, the entity acted upon; but wish doesn’t really “act upon” its complement. Again, even a full clause doesn’t sustain being cast as the subject of passive wish.

I suppose it might be possible to invent a set of circumstances in which passive wish would be appropriate, but it’s hardly worth the effort. If you need a sentence like “He is wished to be here” as an answer to an ill-conceived test question, write it down; but avoid it in serious work.


ADDED:
I should have begun by addressing your premise:

If we make the subordinate clause in "I wish he were here" nonfinite we get "I wish him to be here", right?

This is in fact wrong. I wish he were here and I wish him to be here mean different things. Wish has a core sense of “earnestly desire”, but in practice it has at least four ‘sub-senses’ which are mostly distinguished by the sort of complement employed.

  • PLAINTIVE, with a ‘subjunctive’ finite complement—“I wish he were here”. Wish expresses regret that the desired eventuality is not actualized in the present: “He’s not here, and I wish he were”. This construction is used in all registers; in informal registers were may be ‘de-subjunctivized’ to was.

  • JUSSIVE, with a marked infinitival complement—“I wish him to be here”. Wish is roughly equivalent to want and expresses a (mildly) softened command that the eventuality be actualized in the future: “I want him to be here at five o’clock” or “tomorrow” or “as soon as possible”. This construction is quite old-fashioned, and it’s usually employed only in formal registers.

  • OPTATIVE, usually ditransitive, with an indirect and a direct object— “I wish him luck”—but occasionally attributive, with a direct object and a predicative complement—”I wish him happy”. Wish is roughly equivalent to hope: “I hope that he will experience luck/be happy”. This construction is used in all registers.

  • EFFECTIVE, usually attributive—”I wished him into existence”. Wish is equivalent to cause by an act of wishing: ”I caused him to come into existence by wishing”. This construction is (obviously) restricted to fantastic registers.

Of these, only the optative and effective versions may be felicitously passivized. (Note that the passive optative version ordinarily occurs only with an underlying active context where the Recipient of the wish is the person addressed: "We wish you a Merry Christmas" > "He was wished a Merry Christmas by them".) I suspect that the existence of the plaintive version interferes with passivization of the jussive version: we can certainly passivize other jussives such as desire and require:

The King desires/requires you to be here > okYou are desired/required to be here, but
The King wishes you to be here > ??You are wished to be here.