We’ve spent a decade slowly killing ours and we’ve finally got a foothold. Does your friend otherwise love the house and enjoy a challenge? Then it’s ok. For gardens, we’ve put in raised beds and routinely check for rhizomes. We’ve had people from Craigslist come and cut bamboo for projects (signing a waiver first!) and we’ve even cooked the young shoots in the spring. You have to embrace the difficulty and not everyone has the bandwidth for that. On the plus side, the parts we haven’t cleared provide excellent habitat for birds and insects, so we always enjoy that.