Is prayer obligatory for the incapacitated person who cannot perform it on their own?

If the aunt is no longer able to discern how to pray on her own, then she is excused and prayer is not obligatory for her, because the obligation is lifted from her. This is because whoever's mind has changed to the extent that they cannot discern prayer or fasting, their ruling is that of an insane person. And the pen has been lifted from the insane person until he recovers.