You file suit. First thing is you file a complaint. summons request and pay the fees or you retain an attorney

You need to inquire of an Oregon attorney. You can ask your mother for the documents.

I also do not see a question.......................................................................

You must seek an attorney directly and individually

Without examining the case in detail. no attorney can render a competent opinion

This is a question you should be posing to your counsel

I agree with both colleagues. . .

You are going to need expert testimony to prove that was the cause. It is expensive I doubt any attorney would front those costs

nothing. .

https://www.answers.com/Q/Notice_of_intent_to_participate_in_discovery you can look up all these terms on google