I am from the family side, want to open the HP iPhone code for the deceased brother

I think you're asking how to bypass the passcode so you can get into your deceased brother's phone?

There is no mechanism to do this.

If the phone is locked, you need the code to unlock it.

If the phone was configured with 'Erase Data', then the phone may wipe itself after 10 invalid access attempts.

If you're just trying to repurpose the phone, then you can follow these instructions to reset the phone.

See this document --> How to request access to a deceased family member's Apple accounts