Can my mom sign my dads signature for him.?

Hey I am signing a lease for an apartment soon and the agency needs me to get a co-signer to be notarized. My father is away on a business trip right now and will not be able to be home to sign the cosigner form. Can my mom sign my dads signature for him if he gives her permission? Is there any legal way for this to happen? I heard you can do this if you put your initials at the end of the signature.