Is it permissible for the illiterate mother to continue teaching a comprehensive supplication, while taking into consideration her occasional inclination to supplicate, and is there any fear that the supplication will be answered in this manner?

The mother should be taught the authentic supplications (Duas) and everything beneficial and useful, for the one who points to good is like the one who does it, and guiding one man is better than red camels. There is no blame upon a mother who makes a mistake in supplication due to inability or error; for Allah has overlooked for this Ummah mistakes, forgetfulness, and what they are coerced into. And Allah is aware of her intention and her eagerness for the blessing of supplication.