so nærhet is clossnes, proximity, vicinity. and nærheten is neighborhood or nearby?
Yes, though you need "i nærheten (av)" for the latter. Without the "i", it's just the definite form of "nærhet".
When is it acceptable to drop the word "for" after "redd"?
'for' can always be omitted, it's a matter of preference.
so "Han er red nærhet." is correct?! interesting.
Wouldnt it be easier to say he is claustrophobic?
That would be "Han er klaustrofobisk".
This sentence would be taken to mean that he's afraid of emotional rather than physical closeness.
Det er meg :(
Why can't I say "Han er redd AV nærhet", since it is "of"?
Why redd and not redde? is one for plural?