Having a tenant who is not working, and so presumably not paying rent, could work nicely in reducing the income earnt on investment property - and potentially be more favourable to EP financially in tax return.I suspect the version of care-taking may have been to allow him to stay in the other house that was in her portfolio of property and to ensure he was financially taken care of whilst he was unable to work.
Unless she was doing some full tilt Kathy Bates in Misery routine...
She may consider this ‘taking care’ of him even though such a lucrative arrangement would line her pockets.
I had an ex (emphasis on ex) who would only visit family if he could buy and sell something on the way and end up financially in front. He would 100% see himself as family orientated person. These people are out there.