Yes, you need to choose. If you keep RSChildren, if I'm remembering right, you also need the RSChildren patch for USSEP. If your son has access to the Internet over there can't he just post his LO here on Nexus & ask for a little help? Setting up a fair sized stable mod load order means reading each mod description carefully and adding any of it's requirements, running LOOT to get initial load order and SSEEdit to check for conflicts. I think the best way to sort this out would be for you to start a new game with just your sons mods, run LOOT and see where you are then. It's all for naught of course if your son doesn't have a strong enough laptop.