That doesn't help with the current check, but it would stop it from happening again.

She knows his birthday and SS#. He can't even turn on a computer.

Also have the bank set up the account so that he is the only one allowed to do anything with it, even if she (or others) can verify his personal information. Obviously, if others need access, like family members, they could be included as authorized users.

They could probably shut off access for the current account, but at this point, I think creating a new one would be preferable.

He should tell them he is having trouble getting his payments directly and to not allow any information about his account known. SS could flag it. Your friend will have to not receive any quarterly statements and such to expose his new account. Poor guy..

Long term fix would be to open an account in his name only and have the money deposited there. If she accessed his account due to having his password, change the password.

For his online banking. If it’s a joint account, create a new account and have the direct deposit changed. He could always auto-transfer a certain amount monthly to the account she has access to if he doesn’t want to totally cut her off.

There are offices in major cities eg Chicago, Boston, LA, Den etc.

I guess his best option is to open a new account at a different bank, don't tell her where, and tell the bank he will pick up his statements, ATM card, etc. or get a secret P.O. Box. Call SSA to have them change the direct deposit.
The bigger issue is WHY would she do that to someone she loves (I assume). Does she have an addiction (gambling, shopping...), is she giving it to a child or other relative, sending it to a televangelist, sending it to trump?

She has a spending problem. Their house is full of boxes from Amazon, all unopened.

She had an accident and is in exquisite pain. Since her doctor limited opioids, she's now getting black market pain pills, some which cost $25 each.

revert to receiving his Social Security benefit as a check mailed to his home?

It's been years since they've mailed actual checks. For those who don't have a checking account the alternative is a debit card that gets reloaded every month.

Getting his own account and having SS deposited there is a better idea. Have a password that she doesn't know.

He might want to consider divorce.

Has been like that from the beginning of the year.

Recently, however, they allow leaving name and phone number so an agent can call back. Still have to wait about 40 min, but at least not on the phone.

I wonder whether there is an agency for the senior citizens that can help in guiding on these changes.

there is a social Security office less than 10 minutes from my home. I have never waited more than 15 minutes to have a personal consultation with a live person.