Update: Had a pest control company treat today for the bed bugs. They sprayed all corners of carpets throughout apt, plus mattresses, etc. Tenant is being tolerant & putting up with a lot–I know I wouldn’t like some guy to be spraying blue liquid on my mattresses. But, as another poster pointed out, there is no proof as to how the bed bugs got here in the first place. That is my ultimate defense if this gets in front of a judge.
If this doesn’t work, I will probably negotiate some monetary settlement to have him leave, then throw out the (nearly new) carpets, & treat the apt. fully.