S has no right to the investment account if it was a general asset of the trust. If mom wanted S to get it, she needed to either leave S as the...

If he left everything to his wife, that is what it means. If the will did not, show it to an attorney to discuss distribution.

Make a claim with your insurance company. They will go after his. If you did not have insurance, sue him in small claims court.

How can they have 10k stamps on them and be 925? If you can provide proof through a written test/appraisal, you may be fine, but it seems quite odd.

Yes the deposition can take place over multiple days.

It sounds like all of the money is gone and your sister is committing fraud. If your mother owned a house, you may have a chance to get something....

Speak with an attorney about contesting the new will.

Your friend needs to get an attorney. What you describe is not uncommon, and if she waits without knowing her rights and keeping her sister's toes...

The lender cannot enforce the due on sale clause when a spouse dies. Just keep making the payments, paying the taxes and insurance.

No, subpoenas must be served personally.