I'm going to tell a friend to put on more clothing
why do you want them to put on more clothing?
I do not think they dress well for the weather.
It's none of your business what clothes your friend wears. So you have no right to tell them if they should wear more or less clothes.
I don't want them to look stupid.
You should let your friends wear the clothes that they want to and they are expected to let you do the same.