Husband staying after work and extra 3 hours a day 🧐

My husband is a teacher and usually gets home by 4. He hasn't been been getting home until closer to 8. He's taken off next week for 3 days. The reason he's been staying is because instead of just leaving work for the sub he's making content videos for the sub to play of him teaching the lessons so the kid don't get behind. But I found out from my mom that was a teacher that isn't something most teachers do. They just leave the sub worksheets is this sketchy?🧐