This is one of the best threads I've ever read because everyone is empathic.
As I went through these posts and photos I relived some of my close calls the past 18 years. Of 4,000 takedowns I had two white oaks twist unexpectedly in 2004 and '05 doing $4,800 property damage which I had to pay for out of pocket because my business had not produced enough $ to afford liability insurance. No one was injured but my pride.
Back in 1999 I fell 20' with safety belt and hard hat on, broke a hip and earned no income for five months while recuperating. I had health insurance but it was 80/20 coverage so my co-payment obligation totaled $9,000.
I have never had a tree to barber chair and I attribute that to this book: Faller's and Bucker's Handbook subtitled "Practical Methods for Falling and Bucking Timber, WORK SAFE". The ISBN number is 0-7726-3456-4 on the 1993 edition from the Workers' Compensation Board of British Columbia telephone 1-888-621-7233 (SAFE). I go back through the book at the beginning of each season.
I pray your friend will recover and regain some abilities and you can forgive yourself for making a mistake.
On the woven webstraps I prefer the 3" wide 27' webstraps and would strap a codominant tree in four places real tight rather than two. I had to do this two years ago for an 80 year old codominant red oak 49" dbh that had steel pipe, twisted shank nails, barbed wire, welded wire fence and a horseshoe inside. It was a beast of a job taking 106 two man crew hours, a crane, and we ground the stump nine feet in diameter. Even with use of my Lumber Wizard we could not tell the metal was in the trunk base. I praised God that the job went okay and no injuries occurred.
May all of us pledge to keep helping each other through this web site and email.