Ron usually wasn't the sort to go about hugging people, but the occasion called for it, so he clapped Percy on the back a bit before easing away from him. He tried to look a bit more pleasant than he actually felt at the moment, but as everyone knew, Ron was a bit of a failure at concealing his emotions from the world. He may have had the emotional range of a teaspoon, but that was all that one needed in order to determine that this particular Weasley wasn't dwelling in the best of places at the moment.
"Thanks for coming," Ron said. "You didn't have to and all. But you did. So, er, yeah. Thanks."