You cannot be pilot in command from the "passenger" seat and unless your father is an instructor, then I would question the legality of you "having a go". I would certainly think that it would invalidate the insurance.
You cannot log the hours "gained" so far. You can use a privately owned machine but training for a PPL must be from a licenced airfield. Your father and any instructors within your acquaintance should know that.
Cheers
Whirls