Praise be to Allah.
If it really happened as you say, that this man had lost consciousness during that period – including the month of Ramadaan – when he was not aware of anything as a result of the accident, then he does not have to make up the fasts and prayers that he missed during the days when he was unconscious. This is according to the more correct of the two scholarly opinions, and is because he was not accountable or required to do those acts of worship during that period.
And Allaah is the Source of strength. May Allaah send blessings and peace upon our Prophet Muhammad and his family and companions.