Any person 14 years of age or over who believes that he is in need of treatment and substantially understands the nature of voluntary treatment may submit himself to examination and treatment under this act, provided that the decision to do so is made voluntarily. A parent, guardian, or person standing in loco parentis to a child less than 14 years of age may subject such child to examination and treatment under this act, and in so doing shall be deemed to be acting for the child. Except as otherwise authorized in this act, all of the provisions of this act governing examination and treatment shall apply.