what are the chances to get deported for a federal crime, at the same time an aggravated felony?

A legal resident, with a green card has been convicted of possession and intent to distribute marijuana for which that resident served time (about a year) plus plead guilty to a possession of a stolen firearm for which that same resident did not serve time due to the circumstances, since they did not know at the time that the gun was stolen because the person that gave the gun in place of money for a part of a car did not disclose that, and the gun does not have a record of being used in a crime. What are the chances of deportation of this legal resident with no prior convictions, who lived in the us for 17 years? We've researched and consulted with lawyers but without actually starting a defense case, all we can tell is that there is a good chance he'll get deported but if you are able to say anything more based on the summary here, are the chances to avoid deportation extremely slim etc? Please and thank you.