Hi
@Helenmaryfern . Welcome to the forum.
Diabetes especially T1 is quite a complex condition as you may well be aware.
My first question to you would be..........is your MIL on the ball so to speak?
How as she been managing her diabetes in past years and upto this point?
Is she a person who is capable of still managing her diabetes?
It can be very difficult for someone without diabetes to fully understand the condition.
Does your MIL have a dsn ( diabetic specialist nurse ) you can contact? A dsn should know past control, management criteria relating to your MIL. A dsn should be able to give advice to you as well.
It's difficult to give specific answers without specific questions, but this forum has some very knowledgeable diabetics, who will be more than happy to help all three of you.
Good luck.