A person has the right to leave an employment that they deem as detrimental to their general well-being; at the same time, a debtor under Chapter 13 has the right to convert to Chapter 7, provided that he or she is not ineligible based on bad faith or abuse of bankruptcy process. However, putting the two together—quitting a job then filing for Chapter 7—could possibly raise a red flag as an abuse of process which could be grounds for dismissal under section 707(b)(3).
The conversion process could be complex and tricky. An experienced bankruptcy attorney would better be able to explain the process and things that need to be considered in order to be able to properly go about it. So contact one as soon as possible to be properly advised before the debtor takes any action that might adversely affect him/her.