And as great as it is for him, it's just as comforting for the parents to have David on hand. When they're running late, or tending to another child, or even just taking a shower, they know that their precious newborn won't be alone.
Her son, Logan, was born at just 25 weeks old. She says that seeing Logan in David's arms gave her great relief. "All my anxiety and everything was gone, and I was just filled with joy."
Many recalled the time he had spent caring for their own kids, and the impact it had on their time.
And we're in good company.