A DWI case is often extremely complex and a lot of work for the attorney (if they do their job properly). This is often true even if your son intends to enter into some sort of plea. So you will be hard pressed to find an attorney willing to take on a DWI case pro bono. However, that said it never hurts to ask and shop around. Also, if you son is indigent, he may qualify for either a court appointed attorney or a public defender. Regardless, a DWI case also often has time sensitive elements, so the sooner he can find an attorney the better. Best of luck.