Here are the Google coordinates of the cemeteries themselves - however, the nearest non-4x4 parking may be some distance away! I don't have a road GPS so don't know for sure, but I doubt that the dirt roads are included.
City & environs:
Mikra Cem & Mem 40.578421 22.964582
Lembet Road Cem 40.654015 22.931932 (Parking sparse!)
Monastir Rd Indian Cem & Mem 40.660775 22.897497 (By appointment only! Rough neighbourhood!)
Kirechkoi-Hortakoi Cem 40.625301 23.049734
Struma Front:
Lahana Cem 40.960074 23.190616
Struma Cem 41.018216 23.333681
Doiran/Vardar Front:
Sarigol Cem 40.952280 22.854646
Doiran Cem 41.169536 22.767700
Doiran Mem 41.168371 22.762414
Karasouli Cem 40.994567 22.581461
Further afield but still closely connected with the Salonika Front:
Dedeagatch Cem 40.850967 25.870969 (Locked. Key at Town Hall, tel. +30-25510-26124)
Bralo Cem 38.687394 22.437330
Then Corfu, Skopje, Sofia, Plovdiv, Limnos... How much time does your friend have

Adrian