All praise be to Allah, peace and blessings be upon our Prophet Mohammad.
An unconscious person isn`t obliged to make up for the prayers that he missed while being in that state. However, if he woke up before the end of prayer time, then he should make up for it as well as for the prayer that is usually combined with it such as offering Zuhr with Asir, or Maghrib with Isha. It is also from Sunnah that he makes up for the missed prayer even if its time had expired as the Prophet said: “ Three aren`t considered sinful: The sleeping person until he wakes up, the sick until he recovers and the young boy until he reaches puberty.’{Abu Dawood}
. As for fasting, the unconscious is obliged to make up for the missed fasting days in which he was completely unconscious during the whole day time, and didn`t regain consciousness even for a moment. However, if he had started fasting, then fell unconscious, but woke up during day time, his fasting is valid and he doesn`t have to make up for it. And Allah, The Almighty Knows Best.