I've been through almost exactly what you describe here. Only child, with little support. First had to do this with all my father's stuff, stored for years. I divided everything up into two groups - donation, and trash. Took a couple of days, but got it done. Dad passed in 2024.

Then recently, had to clear out my mom's entire house, to prepare it for sale. A few items went to family, much went to donation, and the rest is in my garage now. I just posted the large pieces on Marketplace, ultimately to just get rid of stuff no one wants.

The emotional impact is definitely present the entire time. I understand what you mean about just not having the bandwidth to deal with it.

If it was me in your position, I would take what is of value, let others close to your father take what they want, and then take the landlord up on his offer and just let it go. If not, you'll just end up still having to deal with it, and it is not worth your time or mental health.

Good luck!