Can a student be counted as late and absent on the same day?

My son is a senior in high school this year & is graduating in 2 days, however; since he was late 3 times due to driving school (all less than 10 mins.) and left 25mins. early one day, they counted him absent 4 days and late 3 days, all within the same 4 days. To be "In good standing" to go on "Project Graduation", a student cannot have more than 12 unexcused absences for the year. He has 14, therefore; he is not allowed to go celebrate with his classmates. He goes to school for 3rd, 4th & 5th block which puts him under the 4 hours a day already, so how can they say, "By law it can't be under 4 hours a day." when it already is? What about the students who only have 4th & 5th block? What about half day kindergarteners? He raised over $2,000 for this "Community Sponsored Event" IS IT LEGAL