Might be worth some short term security precautions like a camera while it is vacant.

A plumber would have to snake a camera through the sewer pipes.

I treated them like I was Dan Rather and they were on camera. 

Your friend will want to offer reinforced walls, built-in and secure irrigation and lighting systems and a state of the art security and surveillance system in-order to separate themselves from what is currently available.

I also plan on installing key phob entry for the lobby, and some security cameras in the common areas to better secure the property and help the tenants feel safe.  

"Get security cameras. 

I'd recommend recording the lease signing so that they're on camera/audio agreeing with the rules upfront

I've moved toward 3D scanning each place (with a Matterport camera) so that if I do get a request for someone to see the unit, I'll send them the scan first so they can do the virtual walk through. 

The camera alone is north of 4 grand and they have monthly hosting fees for hosting the spaces on their server.

Let her watch her home remotely on my iPhone via cameras or even go and visit on occasion, I say.