For anyone that knows me well, my last time back from a break was maybe 6 months ago. I also had this issue. I am in the Dominican Republic still, and the internet here is a collection of local servers that literally blow. My ISP conflicted with the server or whatever was happening, and I could only do 1v1s. If 3 or more people were in game, I dropped after 10 sec in game.
The way I finally fixed this was by tethering a hotspot off of my phone and using THAT internet (my phone data) as my internet source. I am relatively lag free and have gone down from conflicting with everyone to maybe a handful of people on the server. I can play 8 player games no problem with zero lag. Ask him to try this if he has the financial resources to have a smart phone and a good data plan!
