One thing I have found out since my dad died in Feb. is that when you have kids, you cannot be down and sad all the time for their sakes. Yes, it is a sad day. Yes, you will remember your brother and be sad. But, you have children that may or may not miss your brother as much and for them life is life and is going on. They shouldn't be punished and be made to sit around sad all day because of what happened 4 yrs. ago. Yes, it's important and you never want to forget your brother. But, on the other hand, I have learned that life is for the living. And even though my kids absolutely LOVED their grandpa, they get over it quicker than we do, they want to go on with life. They want to have fun. Yes, we still have our crying fits and don't think we can go on another day, but we have to go on for our kids and make life fun. We plan on celebrating and having a great Christmas, even though this will be our first without my dad. The kids don't want to sit around and cry all day and I really don't either! Yes, we will have our sad moments, but for the most part, we plan on having a great time having fun, like my dad would want us to do.
One thing about your parents. They don't have little kids to make happy. They lost their child, so yes, they will be more sad and down trodden, especially at Christmastime. And especially on Christmas Day. But I hope they understand that you still have kids and a family to take care of and need to be upbeat. Kids need to know that life goes on, we miss those who have passed on, but life does go on. They are gone, but not forgotten. No, it is not wrong at all for you to be happy on the day of Christmas!