Animal shelter policy .

Will a neutered male healthy cat brought in to a shelter be released or euthanized if not adopted?

I would assume that each shelter has its own policy on releasing or euthanizing.  If the cat is friendly and adoptable, a no kill shelter with space would be an appropriate place.  Yet if the cat is shy or feral, most shelters will not take them.  Are you looking to place a cat of your own or one you have found/rescued?

I just was wondering if my Kitty Boy would be euthanized if he was brought into the shelter. He has been missing for 5 weeks.

I am so very sorry that Kitty boy is missing.  My guess is if he was social and arrived at a no kill shelter, he would still be there.  Yet some shelters have policies if the cat seems unsocial or unadoptable, the cat will be euthanized after a period of a few days.  Is Kitty Boy neutered?  If not, please know that here in the US, kitten season is upon us.  Unneutered males will roam in search of a mate.  They will roam driven by hormones and food and bad weather will not stop them. 

Yes he is neutered and shy but sweet. He slept on our bed and purred loudly. I hope his shy personality would not be grounds for euthanizing him should he end up at the shelter at some point.

Have you taken a flier with his picture to all of the shelters in your area?  Also you might try distributing fliers to local vets.  They often have people bring them found animals or tell of an animal they have spotted.

I have done all that. I used and followed all the guidelines suggested on the Missing Pet Partnership