Can't install IE11

My brother's unable to install IE11 via Windows Updates, as it reboots a couple of times and then gives up saying it's rolling back the changes. So WU is stuck on that and doesn't show any more recent updates.

I told him to try downloading IE11 and installing it manually but he's reported that does the same thing.

He's also got a problem with Foxit Reader, as even after I uninstalled and reinstalled it IE doesn't show the addon and just displays a black x when he tries to open pdfs in it. It works fine in Iron Portable though.

He has a couple of other problems, one being the PC waking overnight and not going back to sleep. powercfg /lastwake seems to show this is being caused by a component of EaseUS ToDo Backup called Agent.exe, even though the only scheduled backup is set to run daily at 12:00 and has been running then (or around 16:00 on some days when I presume he had the machine off at 12:00). I think I've disabled this schedule now and I edited some Windows Tasks (sync time, regidle backup, etc) that were set to run at 00:00 or 01:00, to 12:00 or 16:00 so I'll see how that goes.

The other problem is that sometimes when he wakes the PC (or finds it already woken) he can't get the display to come on. In fact, he says he checked and Caps Lock/Scroll Lock/Num Lock don't change the keyboard lights and Win+L or Ctrl+Alt+Delete don't do anything either, so it seems that the whole system has crashed on waking, not just the display, even though everything's still powered up, fans spinning, etc.

Anyway I need to fix his IE11 problem first and get that installed and Foxit Reader working in it, if anyone has any ideas?