Evening Mr.V - I think your Elsie sounds a very strong lady, firstly to have survived such a horrendous and painful part of her life - I think her decision not to attend the trial is the right choice for her. The Nazis stole the first part of her young life, so to come back in later years, and rekindle terrible memories, I think would, perhaps, do more harm than good for Elsie.
I would think there must be lots of evidence against this war criminal and other people willing to give their evidence, to bring him to justice. I agree with what others have said, obviously this Nazi will have a team of lawyers, speaking for his defence, and no doubt making the concentration camp prisioners feel they are on trial. It would be emotionally and physically draining for your dear Elsie to attend.
Perhaps another member of your family could attend the trial on behalf of Elsie.
Best Wishes to you both
Love Denise xx