can I sign on to apple with a different apple ID?

My father died a year ago, and for that year I've been trying to access his ipad. Before he passed he changed all his passwords in a haze of drugs and forgot what all the passwords were, so we haven't been able to access them. Long story short, my mother was able to get access to his account finally, but that username and password is not working on his ipad. I was wanting to sign in to his account in order to disconnect the ipad from his account so I can run a fresh wipe on the ipad and finally get it working. Is this possible without messing up my current apple account?