Will not release any information to me or the auto insurance company as to whether we owe any money to them. They will not accept a marriage license and I do not have a power of attorney. State of California.

Why would you owe either one money?
POA doesn't apply once someone dies.
A spouse has access to her spouse's information. Something isn't making sense. Were you not living together?
If you/he owed any premiums, the date of death stops all activity on any accounts, so it doesn't matter how quickly you rush to pay something that might be overdue. Is that what you mean?
Don't they possibly owe you money, at least the SS survivor benefit?

Am shocked they won't release to auto insurer as this is the only way for the insurer to pay any outstanding bill.

What is their excuse or reasoning behind this? Never heard of such a thing.

He has died, there is no POA after death. If there is an estate, the administer of the estate would be required to get info