The hard part is fulfilling the order out because he doesn't have a voice. It's a good thing that the staff treats their lost sense as if it's a normal occurrence. It has taken a while for Lan Zhan to figure it out, but it requires a lot of pointing at the glass bottles and cups, and eventually, the staff understood what they both need, and they carried out the order cheerfully.

Lan Zhan got himself a glass of iced tea while he got Wei Wuxian a glass of chilled liquor. "..." He simply guides the cold glass and wraps Wei Wuxian's hands around it, and there will be a shape of cold glass filled with the chilled drink.