在英语中，"去他家吃饭"可以用下列表达方式表达：

"go to his/her house for dinner"
例句："We're going to Tom's house for dinner tonight." (我们今晚去汤姆家吃饭。)
"have dinner at his/her house"
例句："We're having dinner at my cousin's house this weekend." (我们这个周末在我的表弟家吃饭。)
"eat dinner at his/her place"
例句："Do you want to come over and eat dinner at my place?" (你想来我家吃饭吗？)

这些表达方式都是常见的用来表示"去某人家吃饭"的英文表达方式。