You MUST ascertain who the executor of the estate is. Make checks payable to "the Estate of XXX" ONLY, and to no one else.

Be particularly suspicious of anyone who gets annoyed that you insist on making checks payable to the estate of...
And, if the person died without a will, then an estate must still be established, even for the little things, like final Social Security check settlements, Social Security death benefit, (which is only $250) etc, final IRS stuff, etc. So, some family member, or friend if there is none) will have to go to court and get named executor...don't let anyone tell you otherwise. I know this for a fact because my father died without a will..didn't have a lot of assets, in fact, none, but we couldn't do even the little things without getting that estate set up.

I would take the position that I can only make checks payable to the estate, or release them on specific instructions of a judge. That's IT. Don't let anyone hound you, don't argue with anyone, and don't take anything in writing, either, unless it is from a Judge. Don't believe what you read coming from a lawyer...don't let a lawyer, or the lawyer's letterhead, bully you.

At this point, I would sell/liquidate her remaining items...no executor is going to want the belongings...they're of no value at all until sold, and executors get precious little cut for their work (3% in most states) to justify the learning curve of learning how/where/when to sell these things.

So, some family member, or friend if there is none) will have to go to court and get named executor...don't let anyone tell you otherwise. I know this for a fact because my father died without a will..didn't have a lot of assets, in fact, none, but we couldn't do even the little things without getting that estate set up.

It really depends on the jurisdiction and other mitigating factors. My mother died without a will and there was no need to set up an estate.