Your HSc is an Early Wartime Police (Eagle L) pistol made in May 1942. Unfortunately, there are some serious issues that eliminate it from any collector value.
It appears to have been refinished to something other than its original high polish blue. Both Grips have been sanded and coated with small Luftwaffe (German Airforce) symbols applied. It addition, both Grips are chipped at the tips over the Trigger Guard area. You do not mention if all the serial numbers match although it would not matter in this case.
You are left with a remembrance of your Great Uncle and a fine shooter to take to the range.