ADD parent and ADD child relationships

How are the relationships between ADD parents and their ADD children ?    My son has become increasingly disrespectful toward his ADD father.  Sometimes I think he is a min-version of his irritable Dad.  I worry he is going to be just like his father when he grows up, but he used to be such a happy child.  He is still respectful toward me...sure we have our moments as any parent/teen would but I wonder how much of his behavior toward his dad is hereditary and how much is learned...   His Dad rarely does things with our children, just today my children and I were about to play a board game and my youngest said 'dad want to play with us, all hopeful',  dad replied 'no thanks i'm all set'....  hello how many opportunities are going to be left that your kids wants to play with you...  last year he did not go to one single sporting event of my sons..while i sat in the stands at every game and every other mother and father were there cheering for their sons.  he yells at the kids quite frequently, that is when he even bothers to talk to them at all..  this has been the worst christmas week I have ever had, we were both home all week, one big miserable family... I just recalled that last New Years eve  was the first year I ever let my kids stay up to midnight with me, usually i was just too damn exhausted and wanted them in bed...anyway this was a big deal to them. So my kids and I watched the ball drop, and where was their the other room, not participating/celebrating the new year... 

I have stayed married because I thought it was best for the kids to have a home with both parents, now I am wondering if its actually doing more harm than good.

My relationship with my ADD mother wasn't great but it wasn't horrible either... however she DID things with me like most mothers doand I didn't know she had ADD...not that she has ever gotten diagnosed but there is no doubt in my mind that she is, and my brother was also recently diagnosed..  I guess in my family I AM the one who is different..  my mom, brother, my children, husband...i guess i am the minority.