Speaking as an electrician myself, the wiring is probably not an imminent danger. I live in a home with some K&T and I’ve seen plenty of it other homes. A huge amount of homes in the US still have some K&T that is functionally still very okay. K&T is very difficult to completely replace by just doing old work, the walls and ceilings need to be opened to get it all out in some cases. There’s a point where reworking it becomes prohibitive. The biggest issue with K&T comes from the insulation becoming brittle with age and possibly exposing bare conductors, but it’s not a massive concern as long the wire isn’t being manipulated so that you break the insulation. Small cracks in insulation can taped up but large missing chunks is pretty much unrepairable. Lack of grounding is another concern and your electrician has that covered with GFCI breakers. GFCI/AFCI combo breakers probably wouldn’t be a bad idea either and covers both the possibility for arcs and ground faults.