Would his parents go the extra and pay for him to be enrolled in a language school? That way he'd have a structure to his day (lessons in the morning & afternoon, activities in the evening and at weekends). It would take a lot off your plate too in terms of trying to entertain him all the time. 6 weeks is a lot of time to try and entertain him for.
My brother was, until last year, a director of a language school in North Wicklow and my other brother teaches in one in south Dublin during the summer months to save money whilst he pursues his doctorate.
I know that the language schools around Dublin are heavily networked so, if you wish, I'll ask the lads and see if they can recommend one in west Dublin and how much it would be likely to cost.