Basements, Attics and Crawl Spaces - Estimating CRAWL SPACE excavation/floor support

A friend of mine has been offered a job to dig out 14" deep of soil in a crawl space approx 25' X 12' and also prop up/support the flooring. The person w/the house added the two rooms occupying this space several years ago & has recently been told by a termite inspector that he only has 4" of crawl space & needs it to be at least 18" deep along w/proper supporting of the floors before it could pass inspection. One room is a carpet over plywood that my friend plans on removing to get to the crawl space but the other room is a dining room w/hardwood floors which are not to be removed. This is located in Fairfield, CA Solano County and he has NO idea what to charge or how to go about calculating an estimate. He's a fantastic guy. An old-time local who is NOT in any way a businessman and ALWAYS estimates WAY too low, but he just wants to do right by everyone and for once himself too. He has a couple days to get back w/the estimate so any advice would be greatly appreciated. THANKS!!!

I would start with how many days it's going to take me to do the job. Let's say it's going to take me 10 days & I want $200 per day, in my pocket. If I were going to hire a helper for the 10 days at $100 per day. That's $3,000 labor & that's cheap.

Now we are going to add materials. Count the footings that are needed X 3 bags of cement & sono tubes, for each & add that. The same for 4x4 supports & hardware. The last thing is carting if you aren't going to redistribute the soil around the house.

Get 1/3 down, a 1/3 once the soil is removed & 1/3 upon completion.

Thank you SO much M. Pulpo!!