Where these plants started indoors then moved outside? If this is the case it's most likely your plant is burning a little from the full sun.Leaves curling upwards is a sign of heat stress or nute burn.Since no fert has been in play yet I would go with heat stress.It's best that you try to "harden" your plant by introducing it to full sun slowly,few hours here and there to start gradually increasing to full sun.Water problems,overwater and underwater shows signs of the leaf pointing downwards.Keeping your soil wet at all times is going to create even more problems if it didn't already.It would be a good idea to let it dry out some for sure as stated earlier.If there is no way you can move plants or make a make shift shade structure out of landscape fiber,it should bounce back provided that your friend dosn't "overcare" it. When I move my ladies outside I plant in ground and try to do this when I have a few days of crappy rainy or overcast weather so my plants at least have a little time to "harden" up and accept its new home.