Here's an example of what this individual may and may not be able to at least detect at various pitch and volume levels.

Notice that due to this person's thresholds, the sounds of conversational speech would not be detectable to them. Nor would they be able to hear a watch ticking. The sounds of someone playing a piano in the same room would just barely be noticeable. The sound of a lawnmower would sound slightly louder to them, and the roar of a jet engine above them would sound slightly louder than the lawnmower.

Of course, to a person with hearing levels within the normal range, the lawnmower might be considered annoyingly loud, and the jet engine's roar might cause them to cover their ears.