What does the dimidue family do to celebrate Dimitri's birthday
Oh my gosh they probably have a whole little ritual and everything.
First off, Dedue ensures that Dimitri won’t be woken up early or disturbed by anyone or anything. Dimitri works too hard, so he deserves to sleep in a little bit on his birthday!
Then he (and the children, when they’re old enough) make him a lovely breakfast in bed. There’s about a 50/50 chance that Dimitri will wake up before they’re done and wander off, but the years they actually get to surprise him are excellent! He happy cries every single time, like you’d think he’d learn to expect it eventually but he never does.
Then the kids probably go off and do their own things and Dedue sets about the task of ensuring Dimitri doesn’t do any work all day, usually by pampering the hell out of him. You know, back rubs, cooking his favorite meals and snacks, making sweet love to him by the fireplace...
I don’t think Dimitri is really big on presents, he’d just really want to spend time with everyone. So they gather as many of the Blue Lions together as they can and all have a feast and spend time together as a family.