Ramadan is the month that is the most blessed. I know someone who used to keep a fast and then come to school and eat dinner and when he used to return home he used to act like he still has the fast.
Have you ever seen this happn before and what happened?
If the person is dont it because of health challenges but pretend to fast to respect the others who are fasting then its ok. In fact he will get sawaab for that.
If he did not have niyat to fast to began with then he has to make up for every fast by keeping one.
If he was breaking his fast in the middle then he has to do kaffara by keeping 60 fasts per missing fast.
Yes...I saw people hiding and eating at school all the time. Its pretty common here in Pakistan, I was quite shocked how people don't treat fasting as a farz thing at all.