Validation doesn't necessarily have to mean you agree with them or condone anything... it means you are listening and empathizing. This is something I recommend including into your daily regimen with everyone. After all, nobody likes having their feelings or experiences discounted. What you're really doing is listening to them. I do this every single day with my clients (I own a company and my big hat is sales) and my daughters. I can guarantee you will have improved relationships with pretty much everyone if you learn how to do this sincerely.
And it's ESPECIALLY important if you get to piecing.
By doing this, you're telling them you are hearing them and making an attempt to understand their needs. And just maybe they'll learn how to do it right back with you.
Good luck!
"There are only 2 ways to live your life. One is as though nothing is a miracle. The other is as though everything is a miracle."