Glam, It's okay to be civil with the xh, but you do not want to get sucked into his drama. You've got enough on your plate. If you speak to him, you will need to tell him that he needs to work things out for himself and if it's about the relationship w/his son, the same would apply there as well.
Glam, your xh needs to understand...you owe him nothing. Friendship/being civil, doesn't mean you have to take on his boat load of issues either.
Glam, focus on the here and now and your family. Your xh has been out of your life for a very, very long time and he needs to grow up and take responsibility for his own life. Your shoulders are very broad, but you are only going to be able to take care of yourself, children and deal with the fall out of your current h's crisis.
Sending you hugs today.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.