I've worked as a detention officer for 5 years in Arizona and deal directly with the court system every day. Virginia law will be different but based on the info you have given us he was treated fairly by the courts.
"4 bags" = intent to distibute. One bag with the same total weight may have been treated differently (personal use {within reason})
it was only four "bags"
sounds like mom is in total denial and may have a history of making excuses rather than face the facts, no offense meant.
I have a lot of contact with parents of defendants who don't want to face the facts and start second guessing everything but their child ("the officer was mean", "it was his friends dope", etc, etc)
If it were Arizona he would have been charged with a felony but not faced any jail time . AZ law was changed 5 years ago to NOT require jail time for first time drug offenses in AZ, instead requiring mandatory heavy fines and drug classes.
There may be some recourse with the court to change his plea within a certain time frame.
Your nephew plead guilty or no contest to the charge and he knows what he did or didn't do. Hopefully the 45 days will teach him a lesson and he'll straighten up.