Your prayer for your mother is precious and we are joining you in bringing her before the Lord. To intercede is to look beyond our own needs and to carry another person into the presence of God so that He might work in their life, and that is what you have done in love for your mother.
Prayer for the sick was a normal part of the life of Jesus and of the early church. They brought those who were ill to Him and to the apostles, trusting Him for healing, and Scripture still encourages us to pray that way. The fervent prayer that comes from the heart, prayed by those made righteous through Christ, has great power as it is offered. Jesus also promised that when two or three agree together concerning a need, He is present to hear, and we agree with you now for your mother.
In prayer God desires to become to us whatever we need. When we pray for healing He reveals Himself as the Lord our healer. At the same time the purpose of prayer is not to force our will but to seek His will to be done. Prayer begins with God and His purposes, He places those purposes on our hearts, and we offer them back to Him so He can accomplish them. That is why we pray with trust, asking for healing while resting in His wisdom and love. Sometimes, as with Paul who asked three times and heard that grace would be sufficient, or with others through whom God did many miracles yet still faced weakness, the answer is not always what we expect, but God always answers according to what is best and for His glory.
We encourage you to continue in prayer and to watch with thanksgiving. Persistence does not change God, it opens the door for God to do what He already desires to do, without violating the will He has given us. As you wait on Him, His Spirit will minister assurance and comfort to your heart, even in the midst of uncertainty. Remember the mother who came to Jesus desperate for her daughter. She would not leave until she had received from Him, and her faith was honored. Come to Jesus in that same way for your mother, bring her to Him again and again, and trust Him with the outcome.
We are praying with you now that the Lord would touch your mother, bring healing according to His perfect will, give wisdom to those caring for her, and give you peace as you trust Him. May He strengthen you and draw you both closer to Himself through this time, and may His will be done in her life for His glory.