There are a couple things you can do to eliminate gas in the future, the first is no human food. Dogs process food differently and human foods tend to cause gas in dogs. Make sure your boy is on a high quality dog food as well. Cheaper brands tend to include a lot of fillers and these are common in gas cases.
For now you can add live yogurt cultures to your dog's food. Live yogurt cultures contain bacteria that will help to wipe out the nasty gas forming bacteria that are causing problems for your dog. Peppermint also works very well, crush some leaves of peppermint and mix it into the dog food. The only other thing that will calm this is dog charcoal biscuits which can help to absorb the gas. You should be able to find these at your local pet store. Massage is also very helpful as it will encourage the gas to move along the digestive track quicker. Using heated towels (Heat the towel in your dryer, just not to hot) and wrapping it around your dogs stomach will also help relieve the discomfort.
As for the stool eating you will need to break him of this as it is not a healthy habit for him. This is a very common problem with dogs. The reason why the dog is doing it is it smells good. Dogs digestive tracks work very fast so feces often carries the smell of the meal it once was. Therefore attracting your dog to it. The first step is to consider what you are feeding your dog, quality dog food is recommended as the dog may be lacking the nutrients it needs and thus the dog is eating stool to replace that. A higher quality food will help. High Quality Foods Include Science Diet, Merrick, Blue Buffalo, Wellness, Eagle, and Innova. If you are already feeding a high quality diet then that's great, but if not its time to consider one to help curb this behavior.There are also a couple of things you can do. Add a small amount of canned pumpkin to all the dogs food to help. Pumpkin tastes great going down........coming out leaves it very unappetizing to dogs. It is also good for the dogs digestive track. While there are some products like accent that can be helpful the fact is pumpkin works better and the cost is lower. (Make sure to get canned pumpkin and not pumpkin pie filling). It will not help for old stools so make sure you clean these up. If you have other dogs you can feed them the pumpkin as well.You can also train the dog out of eating stools by spraying them with bitter apple. This teaches the dog stools do not taste good. It may take a few weeks but most dogs learn quite quickly that it is nasty. By training the dog at home they are nasty with Bitter Apple or store bought products like forbid the dog will be less likely to eat stools out side of the home.Walter