Hi rendezvous04,

I can see how straining and frustrating that would feel with re-assurance. Feelings = facts to a pwBPD, its the opposite for a non-disordered person, feelings are followed after facts. At the center of the disorder is the core wound of abandonment, abandonment fears and a pwBPD expect that loved ones will abandon them.
I'm not 100% sure but it's possible that your pwBPD believes that the renovations are being dragged out because of the one worker and he fears that'll you'll reject / abandon him. A pwBPD need a lot of validation and have their feelings validated, its not to say to validate the invalidate the invalid but to validate some of what he's feeling.
Here's a link to a video with validation a pwBPD when they're emotionally dysregulating. I hope that helps.
Video: Validation -- encouraging peace in a "BPD family"Regards,
----Mutt