Simcha Day Camp at Yeshiva Darchei Torah in Far Rockaway has an amazing program for kids with ADHD called the Diamond Program. They have been working for years with kids with ADHD and may be able to give you information about sleep away programs. I think it’s worth it to call and inquire.
(347) 730-1166 or (718) 868-2300 ext 208 Rabbi Goldberg. He’s the middle school principal at Darchei and one of the directors of the Diamond Program.