Finding homeowners.... Any more ideas?

I am also more on the side of embarrassing audacity and would wait for the real estate agent's offer. In inheritance matters, these things usually take longer anyway. By the time relatives have agreed, several years can pass. I know some from hearsay who often go into care but also return again. Even if this is not the case here - these people feel used up when they are suggested to sell their life's work. I myself also have a strange feeling when I find such a real estate agent's card in the mailbox saying "sell your house through us." The way through the legal guardian would be a letter to him - I still see that as legitimate... although the words should be chosen quite carefully there as well.

With all due understanding for the interest in a house, one should not overlook how the owner/the family of the house might be doing.
If my father had to go into a nursing home due to a sudden deterioration in health, the last thing I would want to deal with is annoying interested parties.
I would already consider any further inquiries to be outright harassment.

For once, I actually appreciate the data protection rules.
Calling nursing homes to ask about residents... not even real estate agents are that bold.

Otherwise, just break in... after all, it's almost your house already and it's cheeky of the owner not to sell after one month.

The house has been empty for five months. Contact with the only "family" has been broken off. The letter that was slipped in is a homemade drawing by our daughter of her dream house along with a nice text. I don't think we made it too intrusive.

At the moment, we are just waiting for someone responsible to empty the mailbox. It's been 5 weeks now.
By the way, the tip about the nursing homes came from a court employee (who cannot forward the letter for data protection reasons). But I find this option quite unsettling myself (especially since we can already exclude two homes because my husband knows the managers or staff).

What did you inquire about at the court? By phone or in writing? I would write a letter to the court requesting that it be forwarded to the guardian of Mr. Sowieso.

Every family reacts differently.... but I’d rather get an unfriendly "no, we’re not selling it" than be ripped off by a real estate agent. I don’t want to generalize, but many are simply scams....

I discovered my plot of land during my bike tour, I spoke to a neighbor, he gave me a name, I have a big network and found out his address :-) ... I went there and he wasn’t home (son of the owner, who had passed away before).... I left my number and he called me after a few weeks.... a purchase contract followed, the plot was supposed to be bought by a builder who wanted to build a 6-unit apartment building there, but he didn’t get approval, then I happened to enter the picture.

Under no circumstances would I wait for a realtor's offer. If necessary, inquire about the owner at the land registry office; that is supposed to work in exceptional cases. Maybe you know someone who can perform an online land register query, at the utility provider, city/municipality, district office, etc. Back then, we handed the undertaker of a homeowner a (nicely and kindly written) letter for the relatives expressing interest in the house. The relatives contacted us by phone after a few months and offered us a viewing appointment.

What do you expect from the guardian?

He is obliged to protect the property of the person concerned.

He will not just go and sell the house to you. He has the duty to put it out to tender publicly. Why not through a real estate agent, preferably with a bidding process. That way you get the market price. :p