Legally required to remove all inactive knob and tube?

I’ve got this old house that was clearly built by someone’s drunk uncle. Its sturdy but definitely OLD. The upstairs of my house is open due to a roof resheathing (40 year old roof) so almost all of the knob and tube up there is available-ish. I was just told by an electrician that if I’m rerunning that circuit I’m legally required to remove every bit of the old system (which would require ripping down almost every wall in my house). He also told me that because I’m redoing my roof that its -required- that I redo the knob and tube. I also can’t find that law.

Part of me feels like he’s full of shit. Part of me is like “knob and tube is dangerous so I guess so?”

He’s my first quote (out of 5) so I’ll see what the next guys say, but I can’t find anything that says its a new requirement to remove inactive knob and tube bits OR that you can’t reroof your house if its got knob and tube inside.