so if the attorney gets the charges to a c felony then my husband can qualify for it then?

He is not eligible if the offense is charged under section 124.401(1)(a) or (b). I think if it is amended to subsection (c) involving less than 5 grams then he would be eligible. But you should know that the county attorney could recommend against it. So could be Department of Corrections, which will prepare a presentence investigation that determines his eligibility and potential for rehabilitation while on probation. Even if all the parties were in agreement, the court still retains the authority to sentence him to something other than a deferred
judgement.

5 grams of ANY drug?

I assumed the controlled substance was amphetamine or methamphetamine because larger quantities that would trigger a class B felony involving other drugs would probably be prosecuted at the federal level. If it involves another drug, then let me know and I will check on deferred eligibility.

amphetamine .... yes u are correct