Alarm in clock app. Some settings in Messages or
Contacts.

If i am wrong, i will be interested to
know the details.

If your iPhone is up to date ... Go to settings and check Focus > Do No Disturb or Sleep settings.

Your kid probably set up a schedule for Do Not Disturb OR Sleep functions. The Sleep period blocks everything then wakes up with a musical alarm.

Thanx

3H

i can’t afford the risk to miss a call from certain people or companies. if i was richer, i could use 2x phones.

Now I get up for morning hikes with my club.

You can set it up to allow calls from everyone in your Contacts list, or from a Favorites list that you can set up and amend as needed.
That means that all you miss is the fake phone number call from that nice person advising you that your car warranty needs to be updated, or the IRS needs $300 in gift cards.