If the stock has already been distributed to you as the beneficiary of the estate then you should not need to discuss it with the estate lawyer.
If it is still in the estate, then you should contact the Personal Representative. If you are the personal representative then you should wait. It not advisable to make distributions without following the required probate process.
Simply being an heir under a will does not give you access to the bank information. The other answer set forth the process for obtaining the information. The only additional question I had was who was the account joint with? If the joint owner survived your parent then you may have to talk to them about getting the information you seek.
You should determine if the letter that you have is a valid will, or if he had another document identified as a will. Once you know the status of your letter, then you will be better able to determine your rights and responsibilities to his estate. I think you should find a California probate attorney in your area to help you with the legal issues.
It sounds like you are in a tough position. I would encourage you to focus on the form that SDI is requiring. It would seem beneficial to maintain both types of benefits if possible. I am unsure of what form you are referring to, but it seems that form is rather important. I would assume there is an appeal process for the loss of benefits, either SDI or Medi-cal. You may have to seek appropriate legal advice to protect your benefits.
It would also be important to know whether you currently have the authority to act on behalf of your Mother. Is she incapacitated as defined in the document or state law? If not, does the POA require incapacity in order for you to act?
It does have some mess potential, but a good estate planning attorney should help get it straightened out. Assuming your mother still is mentally able to go through the process, all of our will benefit from having an updated and clear document. Although you did not provide values of the properties, it may be that a living trust is a good solution. The current will applies to assets she did not have at the time she wrote it. It may not go to whom she wants, but rather fall into the residuary...
I encourage your family to decide which of you is going to deal with this and then proactively work with cemetery. They may be responsive to payment arrangements and working this out, rather than expending additional time. It is important to remain in communication and pay as agreed.
Wyoming is an "at-will" employment state, but that could be modified somewhat by the existence of an employee handbook. It is a legally complicated analysis that also depends on the effectiveness of the employment disclaimers. Your boyfriend may also need to review the definition of "criminal drug statute" if he remains aggrieved.