Will Allah forgive me for raising my voice at my mother, who does not pray or fast, and utters strange words during prayer? And how do I deal with her condition and be patient with her?

You must be kind to your sick mother and patient with her. It is forbidden to raise your voice at her. It is permissible to encourage her to pray and purify herself with gentleness and kindness. If the mother reaches the stage of dementia (mental confusion), then prayer is not obligatory upon her, and she will not be held accountable for any deficiency in it. Whatever the mother does in terms of neglecting prayer and fasting, you must honor her, be kind to her, and associate with her in a good manner. The mother is the most deserving of good companionship, and she is your gateway to Paradise. We recommend patience and seeking reward from Allah, and taking the initiative to repent, seek forgiveness, and apologize if you have done anything improper towards her. Serving and caring for her is considered jihad in the path of Allah.