Hi, Christine - I believe that your friend has Ravennagrass, which is the species of Saccharium ravennae.  This plant is native to the Mediterranean region.  It’s been used as an ornamental in landscapes, but some states have classified it as a weed.  In this article, it states that it’s usually used as a screen in landscapes.  Perhaps your friend would be happier if she relocated the plant to a spot further from the house?  This article gives some means of controlling it.  In either case, I would not let it go to seed, if possible.  https://www.nwcb.wa.gov/images/weeds/Ravenna-Grass_Franklin.pdf 
I hope this helps!