hello, I've had dogs most my life and have trained many as well.
This type of pet needs serious patience. Untrained animals have loop behavior. They attach a certain behavior to emotion, situation, behavior.
For instance. When you walk into a door, emotion fills the dog. The dog will next attach that excited emotion to a behavior. If he is allowed to jump up you when you walk into the door, he will continually associated the emotion to the act. However, there is a technique to change it. What to do is while the animal is behaving in an unwanted excitable fashion, you hold them down, until it goes into a calm, relaxed, state and keep it in that state for a few minutes, the release it in that calm state.
When your friend takes her dog out, she should stand at the doorway with the dog and hold it, while letting it go through it's wild emotional state until it calms down. Onces it's calm, she can release the dog in a calm state. If it starts running around the yard. While in the yard, again she should hold the dog down in they yard until it again reaches a calm state. It will start associating a more balanced emotional state. She should continue this until the dog stops.
The dog whisper Cesar Milan is an amazing.... http://www.cesarsway.com/..........he is top in his field and I have used many of this techniques with my dogs and have always worked.
Also, when a dog has a change of diet, like switching one brand of food to another, they will have bowel issues. You need to incoroprate the new food slowly added a little at a time with the old food until it is fully incorporated. However, if you don't know what it was eating before, then it will be natural for the dog to have poop issurs until it digestion is used to the new food. Some dogs also have allergies, so if problems continue, that could also be something to consider. With some dogs the best food is table food and can in the long run be a cheaper option as well as healthier for them. Boiled chichen with rice and small veggies are a suggestion.