Boy, oh boy. This is one situation I have experience in (at least, I think I do).
Personally, I would take the block meal options, so cut out the first option. At my school, I had the unlimited entries per week plan- BIG waste of money. Despite what you might guess, most of the time you usually just end up with 2 meals per day. I was only using around 14 per week, with the closest plan being the 15 per week (and it was the second cheapest).
If you can get all the meals at once to distribute, he could use those extra block points to give to your family, or to other students that might need it. Lots of students don’t eat in the commons because they can’t afford the plans, so there are certainly others he could help out if he finds he didn’t use all of the block points.
On the other hand, you have the smaller block option with the flexible purchase points. These are best if your son doesn’t have much time to eat in the commons, depending on how his schedule changes. I had a similar option at school- really helpful. I don’t know if commons are open most of the day in your son’s school, but having options throughout the campus can save him A LOT of time in between classes.
My main advice: DON’T get the 21 per week option. It’s almost certain he won’t need that many meals per week.