Neighbor Froze My Cacti - some advice needed

[aliazurius]

Greetings,

I have had many of my cacti for 10+ years. After moving from the south to Michigan, I have had surprisingly good luck keeping nearly all my plants going...a heated sunroom is a big reason.

I went on a vacation and was horrified to find my neighbor had left the door open for 4 days with outdoor temps in the low 20's, my estimate is the room got down to 22 degrees. My neighbor says it was only for the first 4 days of my absence and I returned after a total of 14. My plants are dry for their winter rest.

I have taken cuttings and amputated down to healthy flesh of most plants which were leaning over...see photos.

My question is: will a soft cactus survive if it is soft but not rotting? is a cutting absolutely necessary if the plant is soft?
Will tops of columnar cacti- from the bent over part up, survive as a cutting? I know to look for white flesh inside but sometimes I wonder if the core is white enough or not? Will the soft area be "walled off"?

This entire incident is obviously a tragedy for me. I love my plants. I am so confused as to why none of them have cold scars- if anyone thinks there is another cause for this kind of injury please share.

[aliazurius]

notice pilosocereus in back

[aliazurius]

I would also like to add the trichocereus was not etiolated before the freeze! I noticed several columnars look etiolated now!

[Aiko]

The first picture is of a Pachypodium lamerei. Pachypodium needs to be warm. So consider this one lost. It will not recover, but will only get worst and will rot. If there was not frost, it might have rotted away anyway. Keep it in the living room, if you ever get this species again.

The second one should be better at taking some frost, depending on how strong it was. I suspect where it 'cracked', it might rot. If this happens, cut the top off and see if you can save the bottom. If you take off the rotting bits of the top part, you might be able to root it this summer. In the background of this picture, in the middle, I see two more lobside plants. The right one looks to be Pilosocereus palmeri or alike. It will not be that tolerant of cold too. But might be tolerant of just an occasional low temperature, just as long as most days are warmer than cold.