Legal Question in Family Law in Michigan

You need to be more specific. First of all, a plaintiff can't subpoena anything - only a court or lawyer can issue a subpoena. Generally a person does have to provide the other party with a copy of all subpoenas or other requests issued to a person or entity, but they don't have to provide them with a copy of the documentation they obtain, unless already requested through discovery, or encompassed by another request (or required by the court, such as exchanging trial exhibits 1 week in advance of a trial). There are court rules that must be followed by parties to a lawsuit, and they are held to the same standard as lawyers. If you're involved in a lawsuit and do not have a lawyer, you need to learn and comply with these rules to avoid being sanctioned or having your case dismissed (or being defaulted, if you're the defendant).