Hi Jools,
Sorry to hear about the issue you are having with your beloved Jack Russel, Moody! Due to his condition I would be hesitant to suggest anything drastic due to his heart condition but will try to use my knowledge to suggest some easy options to trial.
I first of all would recommend returning to your vets, explaining the issues you are having and requesting an option to be referred to a specialist if possible? If not I would recommend getting a separate second opinion from a different Vet or practice. This is not to say your current vet has done anything wrong or missed anything whilst treating Moody, but instead an opportunity for someone who has had different experience and may have seen similar conditions in previous patients.
An option to potentially help with the cough and fluid build up would be to bring Moody into the bathroom and close the door and windows, turn on a hot shower and let steam build up in the room and allowing him to breathe in the humid air for 10-15 minutes. This will hopefully loosen up any mucus and 'shift' it.
An option to aid with the stomach cramps woud be his diet. Some foods have higher/lower fat contents, or a simply suited to dogs with pre existing conditions or those taking specific medications, for example I have used Royal Canin Urinary for dogs before for dogs being treated for urinary disorders. I only assume this due to the diuretic you mention.
I hope you find some of this useful and I wish nothing but the best for you and your pooch!
Joe
