if you set up a personal fundraiser to help defray medical costs, do you need a tax exempt number?

if you set up a personal fundraiser to help defray medical costs, do you need a tax exempt number?
My son suffered a devastating injury and the specialist is out of network for our insurance. We have an out of network clause but, the expenses are still more than we can afford. He is the only specialist in the area Do we need a tax exempt ID# or a 501(C) (3)?