Who is Mr. Grealy from Autobiography of a Face and what is their importance?

Mr. Grealy is Lucy's father. He is in the news business, and he is far less involved in Lucy's treatments than her mother. Lucy notes that her father sometimes talks to her and seems to want reassurance that she's alright. Mr. Grealy dies after the worst of Lucy's danger is past, and she notes that it's some time before she comprehends the depth of the loss.