In chike's school days, what shocks elizabeth so much that she nearly dies

In Chike's School Days, Elizabeth is so upset by her son's announcement of  his impending marriage to an Osu that the 'shock nearly killed her.'

In the old days in Nigeria, Osu were a people set apart. They were viewed as a type of 'living sacrifice' to the gods, and as a consequence, were not allowed to participate in any of the typical ceremonies or rituals of day-to-day living. Osu were only allowed to marry...