Framing Questions

Hello and I hope someone has some expert advice for the following:

I am renovating an older house in Victoria. Re-framing is being done by a carpenter who seems to be cutting corners by (a) Leaving old, damaged timber in place and just slapping new alongside and more importantly:

(b) A loadbearing bearer under the house needs replacement of approximately 1.5m. My actual intention was to have the entire bearer and the two next to it, replaced. The tradesman has simply put in two new stumps with new 1.5m of bearer right next to the old, leaving the old rotting stumps in place with the old bearer literally crumbling apart. The house is quite low to the ground. What would happen if the old stumps and bearer section eventually give way, and the new bearer section is 4" away from it? I can upload a photo or even short video.

Thank you!