Response:

Your experience of feeling your father’s presence remaining in the room after he left his body is a common experience. 

Just because your father’s spirit no longer had to be attached to his body after death does not mean it had to leave the body immediately. 

The liberated consciousness has the option of staying awhile or not, so it shouldn’t be confusing to you that your father might choose to be with you a little longer since you were in intense grief.

Love,

Deepak