Poor parents and poor little guy. My older daughter was EXACTLY like that around that age. I think some kids just have more active/racing minds and need help learning how to turn off their brains for sleep.
I had to start her bedtime routine really early. We would have dinner, play a while, snack if needed, then bath. After bath we would brush teeth and then head to her bedroom for lots of quiet/winding down activities. I would only turn on her little bedside lamp and we would not leave the room once we finished the bathroom activities. We would read books, listen to her lullaby CDs and sing along, rock and feed her babies... Anything that was quiet and calm but still made her feel like we were playing. After a while she was ready to snuggle in my lap for another book or two. Then l'd turn the light off, put her in her crib and sing a few lullabies. She would still stand up and cry when I left but not nearly as long (maybe 10 or 15 minutes instead of an hour).
Also I found some herbal nighttime tea for kids and that seemed to help. She would drink it from her sippy while we were playing or reading. After a couple weeks she associated it with bedtime and would get sleepy faced as soon as she started drinking her tea. I know hot nighttime tea works for me so I thought she would like it too!!
We weaned off the extra play time and now only do bath, teeth and a couple books. For us the key was consistent (tho for a while long) bedtime routine and plenty of time to wind down before bed. Shes 2.5 now and still fusses a little when I put her to bed but NOTHING like before. She's asleep around 8:30 every night and sleeps solidly until at least 8am. We also leave on a fairly bright nightlight (not sure if she's scared of the dark or not but thought it couldn't hurt). Hope your friends get some sleep soon. Those all-nighters are a killer.