I'm not sure what the family of the woman in question want - if it is to say that the private prosecution shouldn't have been taken over by the CPS because she suffered from bi-polar disorder then I disagree.  Where there is sufficient evidence for a case to proceed then it is up to the defence to demonstrate that the mental capacity of the accused is such that it justifies a not guilty verdict.

A man accused of sexual assault, (or any other crime for that matter), can never be proven to be innocent at their own trial - the most that can be demonstrated is that there is not enough evidence to prove the charge beyond a reasonable doubt.

Conviction of the accuser however does prove beyond a reasonable doubt their innocence. 

Yes it is tragic that the lady in question committed suicide but I don't see that you can blame the CPS for that - her family presumably knew she had mental problems and quite frankly they are the ones who should have been supporting her and caring for her as her trial approached.