Had a great day there in February surrounded by Spits, Hurricanes, Chipmunks and the wonderful Dakota and Lancaster. For an older gentleman it's an easy walk along the side of the hangar. If he was a rear gunner in the Lanc he'll be within inches of where he sat, as the tail is very close to the visitor viewing area. Nothing to clamber over, but the guides really know their stuff and there are usually mechanics working on the airframes.
There are also two separate base viewing areas and as already mentioned, you are likely to see Typhoons up close and personal.
Hope it is a wonderful day for you both.