Zion Pilgrim led his family of 12 children and his pregnant wife out of Gloriavale about four months ago and moved to South Canterbury.
According to a Givealittle page set up for the man by a family friend, a branch "took out" Pilgrim's legs in a firewood accident.
He suffered a broken tibia, dislocated his ankle and damaged ligaments and tendons.
He will not be weight-bearing for at least three months.
"We do have some serious concerns about some of the fundamental ways of thinking and behaving here that we believe are not in line with God's word," the letter read.
"There is also some very concerning fruit that cannot be ignored; the sexual immorality issues and the pre-eminence of sin, pride, lack of love."
The family has been working hard to establish themselves, it says on the Givealittle page.
"They have been doing hunting jobs, butchery, firewood. in an attempt to get ahead and meet their bills.
"But the timing of the accident could not be more inconvenient. They were just starting to get on their feet and were preparing to move house in early February - no mean feat with a family that large."
"This is definitely going to create a financial setback for the family, and stress on finances for the next few months.
"They are a hard-working, likeable and generous family. We really like them and can see that this going to be an extra burden and would like to ask for your help."
On Tuesday afternoon, $368 had been donated to the cause.
To donate, visit the Givealittle page here.
