I so many times find myself referring simply to the Serenity Prayer. To see what I can change, be aware of what I can't and to be able to discern the difference. Not always cut and dry, of course.
We can find ways to ease things but we cannot directly change another individual, we can only change ourself. I am speculating that it can be very hard with PTSD. So many have had incidents during which they had no control and therefore try to gain that control back. I guess what I am saying that is that I am glad you are trying to include your Mom, really reaching out, but that I hope you don't set yourself up for added conflict if she does not respond as you hope she would.