I would not do a thing about his mail unless you feel you need to. My ex has not cut a lot of things. Her car is still registered in both our names. She has not changed where the tax bill goes. I still get calls and mail from the pharmacy, dentist, etc for her. I could make a big deal out of this but I don't. If and when I choose to I will, but for now leaving it alone leaves the door open to build some level of relation ship with her. I also consider it her little anchor to the world she knew and don't want to totally set her adrift. I suspect you feel the same way, so just keep doing what you are doing in relation to these ties. I do agree though that you may make some small demand of him to see if you can get a positive response and change things up a bit.
Twisting on Life's Rope Me53 W53 M20 D21 D19 D16 BD 2-2013 D final 1-2015 _________________________ "Dream about tomorrow, Live for today, Learn from yesterday"