i feel like a heartfelt card that comes like, ten jokes you've thrown together would work well for dad. kinda like a start to your own sassacre tome!
for karkat? i'd arrange a nice movie night where he gets to pick everything, from the food to the movies, even the seating arrangement. spoil him with a little bit of control over a mundane situation. every karkat i've known has DREAMED of that superpower.