Well it will be difficult, because legally the dog is his but there still is a possibility so we cannot rule it out. I appreciate you have developed a bond with the dog and the thought of not seeing him can be difficult.
What you can do is seek the advice of a solicitor to make an application for the declaration ownership under the Torts (Interference With Goods) Act 1977. A case will be heard in a small claims court and it will be the District Judges who has the power to determine who is the dog’s sole owner and they then may direct that this person has sole possession.
A Court is not bound to require that the owner have possession of a dog as this is a discretionary remedy but they may also rule that there is joint ownership so whilst you may not have sole ownership this would still be a positive outcome as you would still get to see Louie and have him legally.
A Small Claims Court will consider a variety of information when determining who owns the dog and will look at things like who takes care of the dog, who pays the dogs day to day expenses, who’s name is recorded at the vets, who is registered on the microchip etc.
A firm you can call who can help you is Cooper and Co Solicitors on 01304 755 557 they specialise in this and can inform you based on further details if you have a chance with getting Louie. He does sound like a much loved member and I wish you well in your pursuit.
I hope I have assisted you today. Please take a moment to leave a rating for me. Kind regards, John.