Tezzie, in order to try to help I'm about to ask you some potentially embarrassing questions. If you're uncomfortable answering them in the open forum please feel free to pm me. Just so you know, I'm a Case Manager for the Department of Corrections and have worked in the system for 23 years.
First off, was his release parole, cr, or max? The reason I ask is that if he is still on supervision then his Parole Officer will have MUCH more information than I do. They know the area and who is more likely to rent to a registered sex offender. For that matter, even if he is completely off of supervision, you may be able to get assistance from the local Probation and Parole office. Unfortunately, you are looking at an uphill battle as many more reputable land lords wont rent to convicted felons of any kind. You may have to go to the seedier rentals but honestly, you best bet will probably to be to rent from an individual versus a company. Much less likely to do a criminal background check that way. Just make sure that where ever he goes, he is in compliance with the regulations.
Second, while I wont ask the amount, I do need to ask if his SSDI is sufficient for him to survive from month to month in a cheapie apartment? A lot of land lords like people on disability because of the guaranteed income.
The more I think about this, the harder it is to come up with info for you. The problem is not knowing exactly where you are so here's the deal. This is what I do to help offenders find home plan information at work. First off, since you are NOT inside the institution, look into HUD or whatever government housing is available in your area. Second, google search "transitional housing for ex-offenders". You will have to wade through a bunch of crap to get what you need but it will help. I did that but, since google searches based on my zip code, it wont really help you much. Third, contact the nearest Probation and Parole office. They will have a lot of the local information sorted out already. If they cant help much, then contact any Minimum securing institutions in your state, especially if they have a reentry program. Any prison with a reentry program has a lot of this information already and while its doubtful that they will send you copies, they may be willing to at least e-mail you links to what they have. I have some friends in P&P here and will contact them to see if they have any advice as well and will let you know if I find something else out. Sorry I couldn't give you more.