Urgent: Repairing My Mom's Falling Floor

My mother’s floor is falling through. When she originally purchased the home, the inspector did not inspect properly or just missed it.

Apparently, termite damage was extensive on one side of the house. The previous owner had someone repair (rig) it temporarily (I have no clue how it has lasted this long).

I am asking for your help to cover materials and costs of travel while we are working.

Labor has been volunteered, and people have offered extra tools as well.

My mother is on a fixed income, so costs are being picked up by me.

With the cost of construction material through the roof, I can't afford to do it on my own, and I appreciate any help that you could give to assist. Thank you so much in advance.