Mom's neighbor died, house has been empty for years. How does this usually work and is there anything we can do to move things along?

My mom lives in an over-50 community in Oregon. Old guy next door died/maybe off'd himself (rumors differ) literally 4-5 or more years ago.

The lender had the place winterized and has basically done nothing since then. Once in a long while they will send someone to clean up the yard if my mom complains.

So far the biggest issue she's had is blackberry vines and rats encroaching from his side of the fence but I'm concerned squatters/tweakers will move in eventually and it will be a serious safety issue for her.

What could be taking so long to resolve? I'm guessing maybe it's tied up in probate? Surely the bank wants it's money back.

What's the most effective place to complain about something like this to light a fire under the process? She and I could even buy the place and rent it out if that was an option to get it occupied.

Thanks!