Are the children sinful for concealing their mother’s hepatitis C virus illness from her, given their knowledge that she does not adhere to medication and medical instructions, and is it permissible for them to perform Istikhara regarding informing her of her illness?

There is no obligation to inform the mother of her virus infection due to the potential negative impact it could have on her. Sheikh Ibn 'Uthaymeen was asked about informing a patient of a serious illness, and he replied that the matter varies depending on the patient: A person with a strong personality should be informed of the reality so they can manage their affairs. However, a person with a weak personality, whose psychological condition is feared to deteriorate, should not be informed, because focusing on the illness increases it. Nevertheless, the mother must be advised to take supplements and avoid anything contrary to her illness, as a form of sincere advice. Deception can be used in this regard, such as having a doctor recommend it, or giving her nutritional alternatives for the supplements.