Wow, ST. I've never posted to you before nor am I familiar with your sitch, but this post hits home.
My H can be VERY harsh with our 3 boys, and even with me at times. Although he will apologize after the fact sometimes. My H also feels that the boys will just have to deal with it. They can't be 'babied' anymore; they need to grow up and learn.
I tend to stick up for my kids, too. Perhaps I should back off as well, but it's tough, you know?!
I also try to explain to my boys that Dad is mad - he's angry - and when people are angry, they say and do some pretty mean things. They don't always know that what they're saying or doing hurts others. Dad doesn't mean to be this way; he's not trying to hurt you. He just gets frustrated. That doesn't mean it's ok, because it is definitely not ok at all.
Right now, I worry about my S12 the most. He's beginning to exhibit a short fuse like H. When I see it coming, I have him stop whatever he's doing and tell him to take a seat for a few minutes. After a short time, we talk about what's bothering him. Most times it seems to help calm him down, but every now and then, I can still see that he is upset.
Very tough indeed.
My thoughts are with you.
Getting over a painful experience is much like crossing monkey bars. You have to let go at some point in order to move forward. ~ Joseph Campbell