So... we all know that cats are the biggest hooligans in the whole dang world. They will do whatever they want whenever they want, and they sure as heck will not be asking for permission. Cats are just jerks like that, it's in their nature, and once they have a target, they will get what they want.
This cat has clearly chosen its humans, and nothing will stop him until they let him into their home, not even a door locked with a code. At all times of the day, this cat will attempt to enter the correct lock code, setting the alarms off and scaring the heck out of the residents. Of course, with the husband constantly letting him in, snuggling with him, feeding him, and generally being adorable with him, we will not be surprised whatsoever if the little hooligan gets adopted lol.