To answer the password question factually: no tool exists that can retrieve another person’s Instagram password legally. Here is what actually happens technically.
Instagram stores passwords as salted hashes, not plain text. Even Instagram’s own engineers cannot see your actual password. When you log in, Instagram hashes what you typed and compares it to the stored hash. The original password is not retrievable by anyone, including Instagram. So the concept of “finding” someone’s password is technically wrong as a premise.
Password reset only works if you control the email address or phone number tied to the account. If you do not control those, the reset path is not available to you.
For parents: the practical options are Instagram’s Family Center supervision tools, device-level parental controls through Screen Time or Google Family Link, or a parental monitoring app installed on a device you own. None of these give you the password. All of them give you something more useful than a password anyway, which is visibility into what is actually happening. 