I have hired an electrician to completely update the wiring of out 100 year old home. He has completed most of the work and started rewiring the wall switches today. He found that the boxes are mounted in concrete behind the switch and destroyed one of the switches when trying to remove it to access the box. Now he is saying the only way to get the switches rewired is to cut holes in our plaster walls above each switch. I have 2 main questions:

1. Is there any other way to rewire these outlets? Hopefully, someone has run across this issue before.

2. If we do have to cut holes, is there a particular way plaster walls should be cut and how are holes in plaster walls generally repaired? Will it cause cracks up the walls to cut into it?

I hope someone can help us figure this issue out so we will know how best to proceed with this rewiring project. Thanks in advance for any advice you can offer!