Where did he say that? I know he said it for social care reform but haven't heard him say it in relation to this and I've read various articles about it.
Maybe we'll find UBI pays for itself as it lessen the burden on an expensive and stretched NHS because all those people with dodgy ailments won't be clogging up the Doctors needing sick/fit notes and taking unnecessary perscriptions to avoid job seeking. This isn't a dig at the genuine who need support.
However, there still needs to be a support mechanism for those who genuinely want to work.