Wrongful deportation?

My uncle was a greencard holder. He was jailed in 1987 for a drug offense. He spent 5 years in jail and was then deported after spending about a year on the street. I think he may have appealed the deportation and lost. I want to know if he was convicted before the Anti-Drug Abuse Act of 1988, if he was still charged with an aggravated felony? If he wasn't, is it possible he was deported wrongfully? Or are all drug charges considered federal felonies which are subject to deportation, regardless of the aggravated felony designation?

Followup question:
Update: He came back illegally.
He was picked up for a U-turn which was dismissed. Unfortunately, he is now in the system, and they recognized that he is here illegally.
If he was originally deported wrongfully(or if we have a case that we should have appealed before), can we appeal now? They are going to deport him again. Is this our last chance to take a stand? Or is this the nail in the coffin?

Thank You

Normally it would be too late to appeal the original decision; but sometimes special writs etc. can be filed. Have counsel review the details closely.