HadEnuff - I've never understood how a mother can shun her child(ren). I can only imagine it's out of 'shame' and fear (not because she has stopped loving them). Your Mum must love you, but I understand your need for 'closure'. Your letter is very 'good', but, as other posters have mentioned, JWs are 'programmed' to see/interpret what the Society wants them to.
Obviously I don't lnow your Mum, but it's possible that she'll interpret your letter as YOU cutting her off, not loving her and declaring that JWs are worse than the Nazis. I think it's important to add (as another poster mentioned), that you look forward to her contacting you as you miss her and wish that you could all be a 'family'...or something like that...good luck, I imagine your heart will sink posting (mailing) it