How can I unlock my iPhone with my imei code

Your family did not properly prepare and erase this iPhone for your use. They should have erased all content and settings so the passcode nor Activation Lock would be present, which both cannot be bypassed. The IMEI won’t help you and is only used by carriers.

Tell your family to follow this:

What to do before you sell, give away, or trade in your iPhone or iPad - Apple Support

Bob Timmons wrote:

From the original post above......the iPhone screen is currently displaying...... "locked by owner"

To me, this implies that the phone is currently Activation Locked.

It is going to be difficult to prepare the phone for transfer in its current state. It would seem that the Activation Lock must first be removed before anything else can happen.

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If the OP's little brother put the phone into the "Locked by Owner" state, then the OP's little brother will need to follow the steps in this article

How to remove Activation Lock - Apple Support

and then follow the steps in the other one

What to do before you sell, give away, or trade in your iPhone or iPad - Apple Support

Hopefully, the OP will clarify things for us.

Yes. It is a bit unclear why the phone would have been "Locked by Owner" if the phone had belonged to the little brother, who had made a voluntary gift of it to the OP. What would have been the motivation to mark it as Lost?

If the OP's little brother put the phone into the "Locked by Owner" state, then the OP's little brother will need to follow the steps in this article

How to remove Activation Lock - Apple Support

Exactly. That is why I noted that the phone must first be removed from Activation Lock in my response.

Hopefully, the OP will post back to clarify where things stand at this time.

IMEI will not help you.

You need the Apple ID and Apple ID Password for the phone.

Help is here: https://al-support.apple.com/#/getsupport

Zachyy is correct.

If the phone is currently associated with your little brother's Apple ID, and locked with his passcode and Face ID, and he wants to give you the phone, he needs to prepare it properly for transfer. Then you will be able to set it up under your own Apple ID as if it were a new phone.

I suspect that if he has any data on the phone like photos, he will want to save or transfer copies of it somewhere else before preparing the phone for your use.

From the original post above......the iPhone screen is currently displaying...... "locked by owner"

To me, this implies that the phone is currently Activation Locked.

It is going to be difficult to prepare the phone for transfer in its current state. It would seem that the Activation Lock must first be removed before anything else can happen.

Hopefully, the OP will clarify things for us.