We only ever see the speaker’s father through the speaker’s point of view, but it’s not too hard to imagine what the old man's life is like. "Those Winter Sundays" tells us that he wakes up early, works hard, and provides for his family. Seriously, he works (in and outside of the home) seven days a week for his family. If that isn’t sacrifice, well, we don’t know what sacrifice is. This dude could use an all-expenses-paid week in Tahiti, if you ask us.
The speaker’s father has sacrificed everything—including his emotional relationship with his kid—to provide the basic tools of survival for his family.
The speaker’s father is just doing what any dad would do by waking up early to light the fires in the house. Nothing special about this guy.