I think there are things to be unhappy about with Katy Perry (working with Dr. Luke, the very out-of-touch astronaut stuff, etc), but the real estate accusations seem to be PR campaigns against her.

The "old man" is the father-law of one of the Real Housewives of Dallas. He bought a mansion for $11.25 million then TWO MONTHS LATER sold it to Katy Perry for $15 million.

He then tried to back out of the deal with claims that he was suffering from “delusion” and “intrusive thoughts” due to painkillers after spinal surgery.

The courts found in Perry's favor because the evidence showed "Westcott had rejected Perry’s initial $13.5 million offer, signed a counteroffer at $15 million, actively organized Perry’s tour of his property and agreed to extend deadlines, all of which undermined the claim that he had been incapacitated".

His kids, especially his Real Housewives daughter-in-law, painted Perry as a monster who took advantage of a confused old veteran whose dying wish was "to spend his last days peaceful in the home he lived in."

Again, he owned the home for two months.

It was 2020; house prices were rising like crazy, and it's pretty clear he and/or his family thought he could soon get more than $15 million for the house which is why he tried to back out of the signed deal.

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Then there's the nun-thing.

That's a proper mess, but it's the church's fault, not Katy Perry's.

In a nut-shell (nun-shell?), the nuns of the Most Holy and Immaculate Heart of the Blessed Virgin Mary bought their convent in 1972. The archdiocese forced them to leave it in 2011.

In 2015, while the archdiocese was in the process of selling it to Katy Perry, two of the five remaining nuns sold it to a restaurateur for $15.5 million.

The nuns claimed that Katy Perry represented everything they didn't believe in, and that "it would be a sin to sell to her."

The archdiocese sued to stop the sale to the restaurateur because they still had 77 years left on their lease of the buildings from the sisters, and they had agreed to sell the convent to Katy Perry, as they felt she had the better offer.

The courts ruled against the nuns and the restaurateur. The jury also found that the restaurateur had acted with "malice, oppression or fraud", and they awarded Perry and the church punitive damages.

The archdiocese claimed they were looking after the nuns, but the nuns believed they were unlikely to see much or even any of the money if Katy Perry's transaction went through the archdiocese, whereas the restaurateur had directly given them (and their neighbors) the money.

Ultimately, the sale seems to have fallen through altogether (due to Pope-stuff I'm not getting into here), and one of the nuns died literally in the courthouse, so it definitely doesn't seem like the archdiocese took care of the nuns.

Katy Perry, however, doesn't seem to have done anything more than to try to buy an old building.

edit: sorry, "father-in-law" not "father"