I want to connect old phone to new iCloud

Did you change the email address for your Apple ID to your email address, or did you create a brand new Apple ID with the new email address? If that’s what you did, rather than just changing the email address for your Apple ID there is no solution except to remember the password.

If you just changed the email address for your existing Apple ID you can just enter the new Apple ID to remove activation lock.

Thanks. You'll need to remove the activation lock first. (https://support.apple.com/en-us/HT201441).

Then, prepare the device for giving away. (https://support.apple.com/en-us/HT201351)

He can then set it up with his Apple ID.

And, you can enable family share, etc. (https://support.apple.com/families-and-kids)

What do you mean? Do you have a device currently logged into an Apple ID? You'll need to unlock it first. Are you trying to set up iCloud on the device?