Is it obligatory to wake a sick mother, who suffers from chronic illnesses and insomnia, to perform Fajr prayer, or should she be left to pray after she wakes up, even if dawn has broken?

Waking a sleeping person for prayer is considered by jurists to be somewhere between obligatory and recommended, as long as it does not result in harm.

Therefore, you should wake your mother for Fajr prayer, unless doing so would cause her harm. This act of waking her is not considered disobedience but rather an act of filial piety and cooperation in righteousness and Taqwa (God-consciousness).

A Muslim must take the necessary steps to help them wake up for prayer on time, such as sleeping early, setting an alarm, or entrusting someone to wake them.