Per your request last week I have had an associate of St. Mungo's whom I trust and who is well-versed in muggle medicine visit Mr. Leyton. At present, it seems that your friend has fallen into a coma. There appears, however, to be no visible sign of a brain trauma, and his physicians are now examining possible causes. At the present, however, he is stable.
I am sorry this could not be better news. My associate has taken an interest in the facility of the hospital, however, and has promised to send word if the situation changes.