My family dog has been an outside dog for 14years, would it be bad for him to change to an inside dog now?

I just recently started looking after my family dog, he is 14 and a jack russell cross mini foxy. He came from living with my parents, now they have moved into an apartment and can't have him anymore. They have kept him outside his whole life, much to my anger. He has had a lot of anxiety problems over the years, I used to let him in when I was alone in the house. Anyway now he is living with me and I let him in when we are home, try and walk him every arvo......would it be best for him to have a free run of the house, be able to sleep inside etc etc, or would it confuse him and make him anxious? Would he bark more when we left the house? I love him a lot and want him to have the best retirement and be happy..........