lol an aww yes your dad must be the one to show dis-interest in him, to start with the bird will do everything in its power to get to your dad! don't pay attention to it, or try distracting it, just sit in same room etc stay relaxed let your dad handle it, it can take some time (as in months)
but it is worth doing as the outcome will be he will be happy with you or your dad, and not have an insane urge to be with your dad all the time, and attack you out of fraustration because your dads not in the same room/not there
but please when ever your dad leaves a room, if there is a door to be mindfull where he is, as there have been many near squished nut, incidents with mine, as she was so fast, and would hang of the door frame, and scream all that behaviour we ignored! to the point of leaving her hung on the door, like a door knocker

she couldn't get out and she wasn't hurting herself,
is yours flighted?? who has the most time to spend with the bird?
an lol they can be little charmers, when they want to be
ok even a slight turn of the head as you go near is a warning!
when you eat (bird safe foods) take some off your plate, do this at a set time each day, with or with out your dad, but your dad cannot do this your dad needs to be doing his, i am not into you act, he will take the food of you an go back to your dad, but let your dad take him off
but i'll warn you now, nut seems to feel whats on my plate is always to share, which is ok, but she won't wait to be offered, and if its hot it could hurt her, so i guard my plate well now lol
nut will still bite me! but its been a long time since she has done it with intent, she will flash her beak at me at times, and yesterday we were playing with some pennies an she clamped her beak around my finger an hung on, lol but no pressure, but i had not moved fast enough