What should I bring to the grad party?

Hello, this Saturday is my friends ex-girlfriend and her twin sisters graduation party. He's been my good buddy since 3rd grade, but I've only known the girls for about a year. I am questioning about what I should bring to their party. I did get them each a bouquet when I went to watch them graduate (me, him, and the girls went to 3 different schools.) They both have iPhones, so an iTunes gift card is an option. I was also thinking about baking a few dozen cookies to bring. They told me that they got me a gift, but I haven't received it yet, so im assuming I will get it Saturday, and if I don't, I'm obviously not going to be rude and ask for it. So that being said, what can I bring to the party, without him getting mad at me? He tends to get mad at me for talking to her sometimes. Thanks in advance.