Well, there are some nonprofits out there doing the kind of stuff you're talking about. One is (or was) Wider Opportunities for Women, which is winding down after fifty years of operation, with its functions being transferred to other organizations doing similar work. There's one project I'm familiar with, called "Economic Security for Survivors"--which works to enhance economic security for survivors of crimes of violence against women. That project will continue under a different parent organization.
PM me if you want any details on that. Nonprofit work varies greatly in salary, but people who can write grants, as well as do the substantive work, are always in demand. I also know people who had established careers with nonprofits who have gone out on their own as consultants, etc.
Just another thought.
I would assume your ex will be held financially responsible for a large portion of your son's college education, won't he? I'm not sure how realistic it is to expect to double your income in a very short period of time.