A first time homebuyer, by most lending programs definition, is someone who hasn't owned a primary residence in the past 3 years. If you lived/owned that home in the past 3 years then it may make you ineligible for certain first time homebuyer programs. The NM Mortgage Finance Authority has some down payment assistance programs available including one called "Helping Hand" for people who have an ABA defined disability (no requirement to be a first time homebuyer). Income & sales price limits apply, however you may meet them both.
Helping Hand: http://www.housingnm.org/helping-hand
The Helping Hand program can be used in conjunction with an FHA 1st mortgage. SSDI income can qualify if it's expected to continue for at least the first 3 years of the mortgage, if it's permanent disability then that shouldn't be an issue to use. SSDI can also be "grossed up" by 125% for qualifying purposes since it is non-taxable.
If you need help feel free to let me know.