Just repeating what the others said.
No, there is no truth to that rumor.
On the park maps and on signs at the entrance to ride queues, you will notice some attractions are marked with a red triangle icon that shows there is a warning. You should look at the warnings and decide whether or not she should skip some of the ones with warnings. In general, WDW will not prevent her from going on any attractions; they issue the warning and it's up to you to decide if it applies to your situation or not. In the rare situation that a CM tells you she can't do a ride, it's because they really think it would be hazardous for her or other passengers.