No, but there is a possibility that if you hire an attorney to represent him in both counties that the attorney can help work out a plea deal for your son so that the sentences run concurrently (at the same time).

Sorry no. Each county has their own jurisdiction that must be addressed in that county. It is possible that if he gets some sort of rehabilitative sentence (such as drug court which both counties have) the other county will consider that and sentence him to complete the other county's drug court as a condition of probation. But he must address each county's criminal case in each county separately.