Will a parent be held accountable for the period of delirium during which he missed prayers, and are there other deeds, besides supplication and charity, that can be done for a parent?

Whoever is afflicted with dementia, delirium, or loss of perception is no longer subject to religious obligations. Thus, they do not incur sin by abandoning prayer or making mistakes in it, and the pen is lifted from them, because dementia is the deterioration of the mind due to old age and removes the capacity for religious obligation. It is recommended for their family to help them with prayer if they desire it, and to accept what they bring forth. As for the deceased, they can be benefited by supplication, seeking forgiveness for them, giving charity on their behalf, and settling their debts, with supplication and seeking forgiveness being preferred.