Is it possible to treat severe and chronic insomnia with ذكر (remembrance of God) and Quranic verses, and is a person sinful if overcome by extreme exhaustion, he misses Fajr prayer?

Seeking healing through the Holy Quran, supplications (du'a), and lawful incantations (ruqyah shari'ah) is permissible for all diseases. It is a complete healing from all ailments of the heart and body, and from the afflictions of this world and the hereafter. Whoever is not healed by the Quran, may Allah not grant them healing. Delaying prayer beyond its prescribed time due to pain and exhaustion is not permissible. However, it is permissible to combine two prayers due to extreme necessity. One must pray according to their ability: standing, and if unable, then sitting, and if unable, then lying on one's side.