Elle, I’m glad to be able to give some suggestions about this matter. I know how difficult it is to have three small children and each of them has another way of dealing with the many languages they’re exposed to. I think there is a lack of studies about multilingual siblings. I’ll write more about this here. – Please let me know if it worked for your son. I’m very interested in learning from others’ experience with this kind of situations. 🙂

Thank you so much for all these suggestions; they are great. I really appreciate you taking the time to suggest resources and ideas. My son likes being the “big brother”, so the reading to his sisters will definitely appeal to him. I am going to try that this evening. 🙂 I will also be making use of the websites you suggested. Thank you very very much. 🙂