Learn English – “He had left all he had” vs. “He had left all”

The past perfect tense usage "had left" is used to order events in the past. The abuse of the girl and the act of everyone leaving the school are two separate past events. The past perfect usage orders these past events so it is clear the abuse happened after everyone left the school, but before the present moment (because it is still past tense).

This ordering of events doesn't change with a repetitive action. Even though the abuse happened on multiple days, each time it occurred was after everyone had left the school. The routine of the action doesn't change the required tense.

He appeared to be punished for what he did.

This is correct. You can also say He appeared to have been punished if you want to emphasize that the punishment happened in the past.

He is to be received the money.

This is incorrect. You can say He is to receive the money or He is to have received the money, but it doesn't make sense to use the passive infinitive form of receive in this sentence.

I allow him to go.

This is fine.

I found this question to be solved by someone.

This is incorrect. Because found is past tense, the infinitive must also be past tense. So you could say I found this question to have been solved by someone. But it's more common to say I found this question solved by someone.