How do you handle a father who says he wants to go home and tries to leave the house?

Redirection is not a trustworthy solution. It only works for a while and does not convince the person of anything; it just temporarily distracts them. Unfortunately, if Dad is a “flight risk”, you will have to take preventative measures. A good place to ask for advice is an organization who deals with autistic persons. People with autism are prone to wandering. Put high locks and alarms on doors, use Wander Guard ankle monitors, put black rugs in front of doors as this makes the person think there’s a hole there. Prevention is your best defense.