Date changing bug and iPad crash

My son decided to change the date back on his iPad air running iOS 9. He anciently discovered that if he swipes up several times the date will scroll back past the 1980s and will lock onto 1 Jan 1970 which will be displayed in the date wheel as "today" He then tried to restart the iPad and now it will not start up.

I have tried to perform a restore using iTunes but the iPad will only get as far the apple logo with a progress bar that does not fill. After a few minutes iTunes shows a error message saying the iPad timed out.

I've tried disabling my computers antivirus software and even tried holding the power/wake button on the ipad for the entire time of the restore process.

Has this happened to anyone else or can anyone help me please?