How can I set up a non-profit, non-interest bearing medical fund for son's medical expenses?

There is no need to set up your own nonprofit organization, register for an EIN or submit informational 990 returns. Simply find and make arrangements with a nonprofit charity in your area that serves families in need or people with your son's medical condition to receive the payments on your behalf. A charity can accept payments in your name and give donors a tax deduction when the organization's exempt purposes are support families like yours. Good luck to you and to your son!

Ms. Harris has given you good advice: don't spend the time and money to set up your own tax-exempt organization. Instead, work with an existing charity in your area that will facilitate what you have in mind. A church might even serve this function.