disabled ipad
my sons ipad is disabled and his home button is broken, how can i reboot it
You probably cannot. Not having a home button is like driving a manual transmission car with no brakes. You can manage for maybe most of the time but when you need them you really need them. Some people use an iPad with a broken Home Button by using Assistive Services but when this sort of thing happens, Assistive Services do not kick in until the iPad is booted and you need it before then.
iPad Service and Repair - https://support.apple.com/ipad/repair/service