You're making a lot of assumptions about her in your posts, you know. That isn't being helpful to yourself at all - you're assuming that she doesn't care, that she wouldn't help if she knew how, that she should be able to just magically know when you need help, that she should anticipate all of your needs on her own and just take care of you, etc etc.

Are you comfortable sharing your diagnosis with us? It might help some of us understand where you're coming from a bit better, as we could look it up and get ourselves an overview. It's clear that communication is a big challenge for you (and who wouldn't be super frustrated with that!) so we could try and help by reading about it ourselves a little bit.

What does your fiancee have as a disability? Perhaps she is having struggles and needs that you aren't meeting as well - there may be some mutual struggles that are conflicting right now.

I'm going to list off a bunch of questions that may or may not be relevant, but they're from things you have said in your posts. (I'm trying to help get myself a clear picture of your situation, because it really isn't very clear to me right now?)

1. What sort of account are you actually trying to open? Is it a savings/chequing account, a loan?
2. Why could you not have your dad help with this account set up?
3. Why is your account set up different from your fiancee's? (This is something that is clearly making you upset, but I cannot even imagine what could make it so that you couldn't have a similar account...)
4. Could you list out the order of events?
(eg.
A. We have discussed my need to have her help with financial and legal issues, and then
B. we were talking about setting up these accounts.
C. I asked her for help but
D. she set up an account on her own.
E. When I learned that, I was upset and told her so.
Finally, F. she told me that she didn't understand my disability) Now, I'm 98% positive that what I've written is completely incorrect. Could you please help me understand how things went? Try writing it into a list and move things around until they're all in the correct order, because I can't tell what happened first.
5. How long have you and your fiancee been together, and why does she not help you?
6. Who else is in your support system? (Who else helps you.. family memers, any workers?)