+ Offer them multiple options of equity/salary and let them pick what works best for their situation. Once you've agreed verbally write it up in an email as a non-binding offer letter, then have your lawyer make it legal.
+ Don't let them push you around. Lawyers are bred to be intimidating - keep that in mind. Don't get dazzled with bullshit. Do research and follow Silicon Valley best practices (like vesting). You'll regret it forever if they convince you to agree to something stupid.
+ Absolutely do not let them handle the equity/financing/control documents for the company. Get an external firm to do it for you, despite the cost. Having someone with a conflict of interest handle your legal documents is Officially Stupid.
+ Do a trial period first. Pay them $N to work for a couple weeks or a month. Don't even talk about it being for a long term gig. Just make it about the project and make it as well defined as possible. It'll be much easier to simply not continue after that then to fire them once they're officially hired.
Sounds like this person should be a cofounder, not an employee.