With actual school begin such a stress factor, look into online schools.
He can proceed at his own pace, with no other students or teachers in his face.
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But with the suicide attempts he need some serious help first thing.. school can wait.
Limit - tv/phone /computer screen may be too visually & mentally stimulating..
Ideas - calm, quiet activities.. painting, crafts ,gardening, model cars/planes etc.. easy listening music, sitting outside in the sunshine & quiet nature.