Bank won’t release MILs money to executor. Is this legal and correct?

Hi all, so my husband is the executor of my MILs estate and he is beginning to gather everything up and find out what all is out there. She had 3 accounts at a credit union-a savings account with my SIL as a co-owner (no money in it came from SIL or was intended solely for her), and a savings and a checking account in MILs name only. My husband had intended to consolidate all 3 accounts but he was told he cannot touch the account his sister's name is on, that it belongs to her now, and that’s fine, she will go down and close the account & give the money to my husband. Now my question is—the credit union allowed my husband to consolidate the personal checking and savings account but he cannot withdraw the money & close the account, they said it’s because unbeknownst to anyone, my MIL had specified all 3 of her children as beneficiaries so all 3 have to go down there together and the bank will cut them each a check. They said they don’t go by what the trust agreement says. Is this legal and correct? He is going to call the attorney on Monday but I was just wondering if anyone knows if the bank is correct? It’s not really a problem that the bank will only cut all 3 a check. It just throws us a curve ball because the money from the estate is supposed to pay for the headstone, MILs person tax return and the trust’s tax return. All expenses were going to be paid before money was dispersed to the kids. So I’m not sure how we are supposed to do that now. We certainly are not going to use our money to pay for these expenses! My husband seems to think the credit union is wrong and should be releasing the 2 accounts to him.

Also is there any way to figure out if anyone cashed in on any life insurance policies in MILs name? Her partner is acting very shady, when the trust was created in March, him & MIL told my husband that there were a couple insurance policies they hadn’t told anyone about. About a month ago, her partner mentioned that all her money would be gone by the time she died and that all the money her kids get would come from the insurance policies. Well.....there don’t appear to be any insurance policies! We found a document for a small employer-provided policy she had when she was still working and it was terminated when she retired but she had the option to convert it, but there is nothing to suggest she actually did that. We will call MetLife on Monday to see if the policy was converted. There are no other insurance documents in her files. Yet he still says there should be a $20k insurance policy. Tonight we had to go over and pick up the deed to the house and her partner said a lot of things that contradicted what he had told me in the past. I’m not sure what he said to my husband a few weeks ago but he asked something about insurance and fires and then tonight he was saying he’s going to try to increase the amount of insurance on the house, I wasn’t paying attention much to what all he said but my husband says his spidey senses are going off and he thinks he’s going to burn the house down for the insurance money!! He also made statements about him and MIL having insurance policies on each other at one time and that she had originally wanted him to get half her retirement if she died first and he’s claiming that very recently she paid him half the value of the car she gave us since he helped pay for it....yet a week before mother’s day he was complaining to me that she wasn’t leaving him anything and didn’t want him touching her money! I knew she should have had more then $12,000 in the bank. I suspect since he handled the finances, he transferred money from her personal accounts to their joint account shortly before or shortly after she passed. She would have never known he did this. He also claimed that they had cashed in every they had 2 years ago and gotten $6k which was used to pay off the house. He was saying all sorts of things about how she wanted him to have everything and that just doesn’t jive. She should have never left things to him over her kids. Her kids always came first. I mean She wouldn’t even give him half the house when she died even though it was half his! (His name was never on the deed though). Instead of selling it when she died and giving him half and the other half going to her kids, she insisted he get a life estate and then the house be sold and the proceeds go to her 3 and his 2 kids. Anyway....I suspect he reached into her personal accounts and may be filing a life insurance claim or 2 but I have no idea how to find out for sure.