Introduce the Teen Table
If sitting at a little table in the kitchen with his younger cousins has your 10-year-old rolling his eyes, rethink the seating plan and consider instituting a "teen table." Set up a place where all of the older siblings and cousins who haven't seen each other in a while can sit together. Avoid awkward small talk with group games. Playing twenty questions or taking the portmanteau challenge can help break the ice.