Most will do it out of the box, so the key is to mess around with the settings until it behaves how you want.
By predictive text, do you mean she hates it when she types 'What ' and it then suggests 'do', 'are', etc ?
Or is it when she types 'Whit' and it automatically changes to 'What' ?
Generally speaking in the latter case (turning auto-correction off) you'll probably have to live with it missing your (seemingly obvious) mistakes.