My favourite idea for Luis  to make friends and feel included would be for the teacher to discuss with the class beforehand of his joining them and how we would like him to feel welcomed. Question them on ways they can make him feel like he is a part of the class. Explain he has the same feelings like them and he wants to be a part of the class. When he arrives he will be introduced and his peers will show some kind of appreciation for him by clapping and welcoming him in their own way.