Either the person signs papers to allow you to manage things or you go to court and convince the judge that the person is not competent to manage his own affairs and the judge appoints you to do so.
Depending on the exact size and parentage, 10 years is a starting point. 15 years is not unheard of.
Put simply, breathing. In more detail, it means to inhale, exhale. It involves lungs, trading Oxygen (from air) for CO2 (waste product from the body, which is good for plants who turn it back into oxygen using photosynthesis).
How short is your hair? Anything more than 1/2 inch will probably show drugs, if in fact Marijuana can be found from a hair test.