You absolutely need a probate litigation lawyer, and the sooner you see one, the better. Take all of the paperwork you have. I would also see if you can check online records and determine the title to the assets. One of the issues will be trying to "lock down" the assets until you can figure out who is supposed to get what.
You have a number of issues that need to be sorted out, including California's community property laws, whether or not the Will is valid, what assets are part of the trust, as opposed to the Will, and who should be in charge of everything.
Find a qualified lawyer as soon as possible! You can click on the link below, "find a lawyer," and try to find a probate litigation lawyer in your area.
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You need to run not walk to an attorney. This is what we call an extremely complex situation.
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The short answer is yes, you need a probate litigator. The "computer" will witnessed by your half-brother and his wife is likely invalid, since beneficiaries may not serve as will witnesses. There are issues of undue influence involved in your fact situation; as well as issues of money tracing (the estranged wife).