I want to do something special for my dad?

Our beloved golden retriever died suddenly yesterday. He loved that dog more than anything. I feel so bad because he works SOOO HARD to give my 3 siblings and I a great life. He hates his job, works ungodly hours, and he and mom barely speak to each other (they won't divorce because of us kids.) He's always wanted to move too, but didn't because it's such a good neighborhood for us to grow up in. He's made so many sacrifices for us. My mom has many health problems, and had cancer last year too. He was wonderful all throughout the experience. She's tired and weak a lot, so after his ridiculously long and tedious day at a job he hates, he comes home and wants to clean, fix up stuff in the house, among other things. (I've since not let him, and done this myself.) It's just that... this dog was this great source of happiness and love for him. It broke up an otherwise tedious and tiring day, and made him happy. Mikki (the dog) loved him the most. I've never seen him cry so hard in my entire life. It was almost scary to see my father like that. Hysterically sobbing. It broke my heart in a million pieces, not only because I loved this dog to the moon and back, but to see my dad, and think of how absolutely amazing he his...and then this. I don't know what to do. It makes me physically ill to think about it. I love my dad so much, and I appreciate everything he does....I need to do something special for him. Please, do you have any suggestions?