If you're there for a pm only, you might be as well to take a minibus trip with one of the battlefield tour guides.
For example ...
I think the Cloth Hall Museum may be closed for refurbishment but that's easy to check on t'internet.
Get your lad to do a search on the
Commonwealth War Graves Site before you go. Pop in your own surname or that of swmbo's and you'll get plenty of hits in the Ypres area. Even more effective of course if you know of an actual relative who is still over there.
Toc Aitch (Talbot House in Poperinge) is well worth a visit as is the German cemetery at
Langemarck although it's a very different experience from visiting a CWG cemetery.
There's the trenches at
Sanctuary Wood just outside Ypres. Don't let him buy owt from the slimy f%ckers who run the place but it is a very interesting visit and gets over some aspects of the trench experience.
I've done visits with my school and we always drop our pupils off at the
Canuck monument at the top of Paaschendaele ridge and then "march" them down the hill to Tyne Cot. 20 minutes walk with five months and 500 000 plus casualties to move that far in 1917. Makes the point well enough.
Finally, there's
Essex Farm Dressing Station There's even likely to be some poppies growing around there so your lad can pick one which is likely to be "related to" the Poppies McCrae wrote his poem about.
If you can stop over for the
Last Post ceremony at the Menin Gate at 20 00 hrs, it rounds the day off very movingly.