Student or Learner
a. My Dad will watch television on Sundays.
b. On Sundays, my Dad will watch television.
c. My Dad will sit in front of that window on Sundays and think about his youth.
d. On Sundays, my Dad will sit in front of that window and think about his youth.
Do these sentences tell us what my Dad does
1. every Sunday
2. on some Sundays
The assumption is that the sentences are not about the future. That is a possibility, but that is not the intended meaning.