How much longer can my MIL (86) survive since she has been on IV since the last 2 weeks?

She is clearly sad and uncomfortable and knows her time has come and is unable to eat or drink anything. We are at a loss watching an always independent lady in this condition. We are by her side day and night, holding her hand, and singing her favorite devotional songs. We do not know what God has in mind for her and hope she doesnt suffer.