My mom died a week ago and her roommate has everything and won't give her stuff to me and my brother, what can we do?

That's a really tough one. First, if Mom's roommate is over 65 (and this is Oregon, right?) be extra extremely careful not to do anything that might be construed as harassment or elder abuse. First, point out to roommate that she can't keep your mom's stuff that's illegal. On your mom's death, her stuff is owned by you and her other heirs at law. It's your stuff now. You didn't indicate what your mother owned. Even if there is no real property, wouldn't there be bank or brokerage accounts, a vehicle, something else that needs to be transferred? If yes, all goes into probate together, and the cost of probate is paid from the decedent's assets. You may be able to do a small estate affidavit, which only costs $110 or so to file. Call the Oregon State Bar and get the names of some probate lawyers in your area. They agree to do a low cost initial consultation. Go to the lawyer's office with a list of what your mother owned (best guess), and see what solution can be thought of.