She stays away from him and keeps her claws folded behind her back. It would be wrong to try to make him like her, of course, but it's fine to avoid frightening him further. She doesn't care what personal reasons he might have to worry. Of course he's in a hurry to sell - owning land in the whole city is going to be pointless soon unless you plan to build a shelter. Or maybe he has debts, or wants to raise money for a bribe. The furniture is already gone without a trace, so he probably didn't think it was possible to sell the house at all. Or maybe the custom here is to sell houses empty.
It's a good house. Fancier than she'd prefer to pay for, but maybe Mr. Cromwell will like that, and the equipment and the amount of space she thinks she can negotiate for are excellent. If the city is abandoned, the location is convenient for salvaging the factories, and being within the city and away from the ocean might protect from the worst of the weather.
Kireh has little experience with money. When she was alive, she didn't have money of her own until her husband died and she joined the army, and then she still didn't have much opportunity to spend it before she was killed. Mortal followers of Marra use money with non-Marrans, and in cross-hierarchy trades among themselves, but it's risky to haggle: discussing a deal is a way to build affectionate emotions. It's better to set a price in advance or ask a shared superior to set terms for a contract.
One thousand pounds seems fine? Renting at twenty pounds a month would pay off a loan in fifteen years, which seems like a normal amount of time, in the hypothetical where life continued without the oncoming cold?
"Immediately? It will take me at least an hour to gather information and arrange a loan. Is that acceptable? Also, I want to read your mind, or get similarly strong assurance of your honesty by some other means. I will pay you the average of one thousand pounds and your actual minimum price."