Even though your boyfriend's felony conviction is from a long time ago, federal law (Title 18, United States Code, Section 922(g)) and most state laws still prohibit him from possessing a firearm - at any time, for any reason, except in the limited circumstances of a true life-and-limb emergency.
The likely length of your boyfriend's sentence will depend on a number of factors, including whether he has a plea bargain or is convicted at trial, the particular judge who has his case, and his criminal history. For a federal charge, there are sentencing guidelines which give a suggested sentence. In the context of using the gun for hunting, the most important factor will be his prior criminal history and in particular whether his prior felony conviction is a crime of violence or a drug trafficking crime.
You should consult an experienced criminal defense attorney in your area if this involves state charges. If the charge is a federal one, the attorney you hire need not be licensed in Virginia - you should hire an attorney experienced specifically in the federal criminal system. When I was a federal prosecutor, I prosecuted a large number of these felon-in-possession cases and I could represent your boyfriend if you wish.
Your boyfriend needs to find an attorney who is experienced in the local jurisdiction. Virginia's hunting laws are very specific, and lawyers from your area will likely know the game wardens involved in this case. You'd be surprised how often lawyers who live in your area are confronted with hunting-related cases!
Simply possessing a weapon can be a new crime for your boyfriend, unless he was eligible and filed to have his rights restored. This process can be tricky and time-consuming, but is worthwhile after so many years of good benavior. Your boyfriend should find an attorney in the area who knows the jurisdiction.
By this point, your boyfriend has probably already been arraigned, and a bond set. In Virginia, there is a presumption that each person will receive a bond, unless the prosecution can prove some specific things. One is if the accused would be a danger to the community. A judge has a wide range of options at his or her disposal, and usually uses a combination of a few of them to set a bond. If you are unhappy with the initial decision, hiring an attorney who knows the jurisdiction can help your boyfriend, as that attorney can file a subsequent bond motion.