What should I do regarding my daughter who suffers from a chronic mental illness (bipolar disorder) and did not fast last Ramadan due to a relapse that affected her consciousness? And am I, as a mother, sinful if I am unable to wake her for prayer due to the severity of her illness?

If the illness is severe and causes loss of consciousness during Ramadan (definition), then neither make-up fasts nor expiation are required. However, if the illness is merely depression, with consciousness remaining, then if her recovery is hoped for, she must make up the fasts. If her recovery is not hoped for, she must feed a poor person for each day. And if she does not wake up for prayer, she must make up the missed prayers upon waking. It is permissible for her to combine prayers to alleviate hardship.