The driving restrictions only apply to the area bordered by Caen and Bayeux inland to the South, and Omaha to Sword Beach by the coast. And it only is in effect on June 6th—so far there are no restrictions before or after. This is mostly for security for heads of state, and logisitcs for the few honored vets. But you should be fine on June 7th and 8th, and fine in Sainte-Mère-Église all week. Although there may be significant traffic around Sainte-Mère on the 6th and on either side. The town packs a large party and multiple ceremonies. But driving is the only way to get around the area anyway, so that's your only option other than walking (Normandy is a huge area). IF I can find it, I'll try to post a map of the restricted roads.
btw, Liesville-sur-Douve is very close to Sainte-Mère-Église, Carentan, Sainte-Marie-du-Mont, and somewhat close to Utah Beach. It is a very central location for many of the events in that area, and you're fortunate to be able to stay there. Most of that area has been booked for two years. And on June 9th, there is a huge parachute drop and ceremony following it by the U.S. and Allied airborne troopers nearby (we're talking about many, many, many plane loads of paratroopers). This happens at the LA Fiére Causeway, which is technically in Sainte-Mère-Église, but a few miles west. Sainte-Mère is also the base and hang-out town for the visiting U.S. military.
I'm sure you'll have a great time, and what an honor to have your son's band part of the ceremonies! FWIW, I'll be parachuting into Normandy from France on June 5th, and will stay through the 9th in Carentan (I've visited the area seven times, five of which were D-day anniversaries). PM me if you want any more info.