How can I grant temporary guardianship of my minor son to my brother?

You can prepare a temporary guardianship for 6 months only.

Give your brother a durable power of attorney giving him the power to obtain medical help and to discipline him and make educational decisions. It must be durable because if something happens to you and you become a vegetable, he has to have the continuing power. If it is not durable, it ends when you become a vegetable.

It would be helpful to know more about the location, rights, and desires of the biological mother, assuming she still lives and more importantly if you have been in contact with her about your upcoming situation and desired plans. Having her consent will only make the process easier, quickly, and with less tension. In the event the biological mother has unfortunately passed away or is otherwise in agreement with your plan of action, typically you should not need to file anything with the courts. In fact, the special proceedings division of the courts that normally hear guardianship matters technically don't have jurisdiction to appoint a guardian for a minor child if the parents are still alive, even if they consent. Also because those types of proceedings are really more for permanent or long-term and usually due to the incapacity, death, or unfitness of the current biological parent(s)/guardians. You would be best served by putting something in writing, specifically a custody agreement. If you can't reach an agreement, then you may have to actually go through the general court system to get a court order (family court, not special proceedings court, as noted above). If any of the above sounds too complicated and/or expensive (especially if you were to hire an attorney since that is always advised when it comes to legal documents or court filings), at the very least you could try to put something together on your own that puts in writing what all you plan to do and who all in agreement, even if not a full blown, detailed custody agreement that an attorney might do. And then you could at least have your document reviewed by an attorney to see if it's sufficient for the short-term situation you will be in. Overall, if your main goal is that your chosen caregiver will be able to communicate with your son's school and medical providers, as well as have access to important information/records with each of these 3rd parties, you may want to also look into something called a "Temporary Guardianship" form to at least use with these 3rd parties to "get by".

The law allows you to name a short term guardian of the child, but Mom must consent.