How to prevent changes on the iPad I have an iPad with iOS 9 that is used by technological illiterate people of my family. These persons use basically facetime, messages and safari.

They manage that relatively well but if for some reason something happens that prevent them from doing that, they panic and start tapping in a lot of things, swiping here and there, tap tap tap and 7.32 seconds later they have managed to logout from messages and facetime, disable wifi, put the ipad on airplane mode, add members of the family to the facetime blacklist and all sort of things.

I have to spend hours reverting the device back to a useful state and they get pissed because they have to wait for me to use the device again.

Is there a way to prevent them from doing these changes but let them use facetime, safari and messages fully on the ipad?
Apple's Parental Controls can restrict many things.

If that's not enough you can create profiles with Apple Configurator that allow additional restrictions.

You could also teach your family members how to fix the settings they changed accidentally. Give one of them the messed up iPad and tell them the steps to do. If they don't remember next time, make them write down the things to check. Print out the checklist and stick it to the back of the iPad.