Tuck is thrilled to see Winnie because he hasn’t seen a child in a long time.
The Tuck family is immortal. They do not get many visitors, because they try to keep hidden. If someone found out that they were immortal, it would be terrible. People would ask too many questions, and want to know where the spring of immortality was. The Tucks will do anything to avoid others facing their fate.
When Winnie sees Jesse drinking from the spring and wants to drink, Mae and Jesse can think of nothing else to do other than kidnap her. They want to have time to explain the situation. They take her to Angus Tuck, Mae’s husband.
He straightened and peered down at her, and Winnie, looking back into his face, saw an expression there that made her feel like an unexpected present, wrapped in pretty paper and tied with ribbons, in spite of Mae's blue hat, which still enveloped her head. (Ch. 9)
Angus says that seeing Winnie is the best thing that has happened to him in eighteen years. He is thrilled to see a child. Mae explains to Winnie that the Tucks only have each other, and their children Miles and Jesse do not come home often. Ma and Pa Tuck have each other.
The boys, now, they go their separate ways. They're some different, don't always get on too good. But they come home whenever the spirit moves, and every ten years, first week of August, they meet at the spring and come home together so's we can be a family again for a little while. (Ch. 10)
Miles had a family, but his wife left him when she found out he didn’t age. Jesse never married because he became immortal too young. The boys wander around, coming home every once in a while, but Ma and Pa miss them. They station themselves in a house for a decade or so and then move to another one before people get suspicious.