Here is the second part to Diana's email...
When he was a puppy he was very well litter trained. However, after he was left at a family member's house whilst my mum and myself were away, he seemed to have been neglected in some ways (or so me have assumed) and certainly had not been taken out for a while and all the litter training was, well, "forgotten" by my dear best friend. He is now an 11 year old male (not castrated, no other pets or children at home), and has problems with urinating in the house since then. He is taken out for walks regularly (at least 4x a day and let out in the garden in between) and has no bladder problems, UTI infections etc. His bladder is thus never bursting! He tends to urinate objects that are not meant to be where they are placed (e.g. a plastic bad or coat on the floor). But generally also urinates chairs, armchairs and curtain corners. My mum has thoroughly washed the places where he has urinated (even using diluted bleach on the carpet) to try to kill the smell but to no avail. It is impossible to catch him in the act and punish him accordingly as he does this when no one is around. Positive reinforcement from doing it on walks has not helped either. This problem can be quite embarrassing and he cannot be taken to friend's houses as he will urinate everything there too and has caused us a lot of impossible hassle over the last 11 years. We can't keep him outside in the garden (he's a clingy indoor dog) and have no idea what to do. Obviously neutering him would not be ideal (he has a heart murmur and too old for that sort of thing). I also could not afford expensive behavioural classes either.
I've personally not spoken to the vet about this (it's embarrassing for me as an owner!). We have tried and given up on what on earth to do. Do you have any advice? Is it too late to change his ingrained behaviour?
This is certainly a tough case, Diana. As you mentioned, the obvious first step would be neutering. Though I agree that his health may prohibit this surgery, there are also ways to do it safely. If the murmur is mild and stable, there are anesthetic protocols that can be safely used. However, another thing to consider is that at his age neutering alone may not be enough. If the problem is largely influenced by hormones (specifically testosterone), then you won't have much success without neutering him.
One recommendation is to go back to basic housebreaking techniques, especially the "crate training" method. You may already be familiar with this way of training, but if not you can easily find instructions on the Internet and in any good dog training book. This method is more than simple positive reinforcement, though that is certainly part of it.
If improper housebreaking when he was young and hormonal influences are the underlying cause, then the above recommendations are all that you can really do. If there are other behavioral causes such as anxiety, stress, and other issues, then medicine may help. Many cases of inappropriate elimination have been helped by pharmacotherapy, though you need to find a vet who is comfortable with this kind of behavioral treatment. This kind of problem can be difficult to handle, so you want a doctor who has handled these situations before.
In the end, this isn't going to be easy to fix, in large part because it has gone on for so long and because he's not neutered.