Can I put an AT&T iPhone 5 on Verizon?

My brother-in-law broke his iPhone 5 I want to give him my old one but I have AT&T and he has Verizon will it work

It will not work. Verizon will not activate a non-Verizon phone. Plus they use a CDMA network and AT&T is GSM.

Nope, not compatible. Verizon doesn't use SIM card and AT&T iPhone are not CDMA capable.