When we look for somebody and cannot find him, what reply would be appropriate?
- He is not to be seen here
- I can't seen him here.
If anybody ask for this person, what should we say?
Neither of them. The first one doesn't convey this idea, and the second one is grammatically incorrect.
He is not to be seen here.
Conveys a warning, almost a threat. The speaker clearly doesn't want this person to show up, and is telling anyone present about it in a threatening way, as if he was telling them "you cannot let him enter" in an implicit way.
The second one is correct if you use the verbal root "see", since it follows an auxiliary (can) :
I can't see him here
Varun KN's answer gives you more expressions to say this, my favorite being
I cannot seem to find him here
Neither. Also, the second sentence is grammatically incorrect. The corrected sentence would be:
I can't see him here.
But I would suggest you to use neither. Why don't you try a few other sentences, like:
- I cannot seem to find him here.
- I can't find him here.
- I do not know where he is.
- I'm not sure where he is.
- I'm unaware about his whereabouts. *
- I'm uncertain about where he is. *
(* - This would be appropriate if the person has been missing for quite a while.)
There are countless more ways you could say this. Although the answer to your question is primarily opinion based and is really broad, I wouldn't recommend either of your suggestions. You could try the above sentences, which should convey the same meaning.
Also, A good suggestion by Araucaria:
- He is nowhere to be seen.