It depends on what she wants to be treated for. She can be treated for anything sexual/reproductive without the consent of her parents, but for many other things she needs to be 18.
Depends on the state you live in. Check your state laws. It differs in every state.
All dog bites should be treated. Seek advice from your doctor or nearest emergency department of your local hospital.
A valid passport for the child and a visa if the country you are going to requires one. You should also have a written consent to have custody of the child and a Power of Attorney drafted by an attorney so that you can have the child treated in a medical emergency. See also information in the related question.
It probably depends on the state and the situation somewhat. However, usually if the doctor has permission from one legal guardian (it doesn't need to be both), they can administer meds. Also, in emergency situations where the patient is considered to be at imminent risk of hurting themselves or others, meds may also be administered without any consent (until the crisis abates). Finally, if the minor is emancipated, only their consent is needed.
No. There are no checkpoints as there are between countries so there is no way for the government to regulate that. It is perfectly legal for grandparents to travel in the US with their grandchildren without any documentation. Really no one need any documentation to travel with anyone inside the country. If you want to go to Canada, a notiraized letter that has the signatures of both parents is required.
A hospital can treat a 16 year old minor without getting the consent of the parent depending on why the child is being treated. For example, in an emergency situation, the child will generally be treated in the ER without permission from any parent.
In non-emergency situations, hyperkalemia can be treated with a low potassium diet
As he is sick and needs treatment and he has agreed to take it, it should be alright.
This is a problems that must be medically treated quickly. Call your doctor immediately. They will most likely tell you to go directly to the emergency department.
Medical emancipation deals with emergency situations and often dealing with birth control issues. A minor can be treated for life threatening issues even without parental permission. If they had to wait on the parents, it might be too late.
The emergency condition of anaphylaxis is treated with injection of adrenaline, also known as epinephrine.