Maybe have a word with your Dad ask him to put your name on future presents, tell him you will contribute a little towards the cost, this would solve you the hassle of having to find a suitable present for someone you are not that close to, i don't mean that in a mean way, just that you might not know what to buy them. I think your Dad would happily do soemthing as small as putting your name on a card/present if you explain to him that it would make to feel more accepted in that part of your family, he may not have realised you feel this way, and telling him might make him want to make a big effort and do all sorts to make you feel included.