Where to place my elderly cat

Question
Hello, I am in a hard situation. I have had my 13 year old grey tabby since
he was born (we fostered his mom when she gave birth to her litter). Now
I have an elderly relative who is coming to live with me (next week!!) and
she is severely allergic and has breathing problems, so I have to give my
cat away.

This is proving difficult because he (altered male, 9 lbs) is in great physical
health but suffers a couple personality disorders. First off, he is fairly
unfriendly and doesn't like more than a handful of people in my life (he
really only shows affection towards my husband and me). Second, he has
anxiety issues and displays them by pooping on our bed, the couch, or our
clothes when he is upset (it appears that the act coincides with whoever
he is upset with, e.g. If the dog upsets him, he will poop on her bed, if I go
out of town, he poops on my side of the bed or my spot on couch).  My
husband and I have tried everything from a cat whisperer, putting him
outside, anxiety medication, none of which alleviate these problems so we
have chosen to live with them out of love for our cat.

But I fear these behavioral issues make him unadoptable (I have consulted
two animal shelters). And I have no friends or family who want him.

I did find a possible solution: a friend of mine works with a man who has a
large property and takes in cats (he has about 8-10 now). He builds them
little personal houses and gives them free range on his property.  

Which sounds very nice, but leads me to my question to you...
This would be a complete lifestyle change for my cat. He would not be
indoors (currently, he asks to go outside for a little bit each day, but
comes back in after exploring), he would not have the level of human
affection he gets (demands!) -- no sleeping in bed and on laps -- and I'm
afraid his anxiety will make it difficult to assimilate, and he will be
miserable.

So my question is... Would it be in his best interest emotionally to just put
him down peacefully? Or am I being a worry wart and his chances of
assimilation to a new lifestyle are great and it would be in his interest to
set him up in this new place?

P.S. He has shown that he likes other cats, he has a few friends in the
neighborhood (and a 'girlfriend') that he sees when we let him outside.

Thank you for your help! As you can see this is a tough situation and I just
want what is going to be easiest on my cat...  

Answer
I hate to tell you that no matter what new situation is posed to him, he is not going to adjust well as he's spent his entire life with you. Are you positive that your relative will be allergic? Because I would honestly give it a try and see what happens since he's not that friendly and hopefully your relative is only allergic if physically around the cat. If I seriously had to choose what would be best for him emotionally if he cannot be with you, I would say to put him down. But I would feel so much guilt over having to do this just because a relative with allergies is moving in.

To give you some advice on his anxiety issues, the best thing to do is make the situation as calm and relaxed as possible including the way you act around him as well. The more at ease you feel, the more he'll sense it and relax as well.

Please let me know what you end up doing.