Depends on how many of them are on disability. Four adults on disability could mean that they make enough to pay rent and eat. If they are on disability, they may not have large funding changes unless they get a great job.
I work in a program for mildly to moderately disabled youth. Many of them (even those who get high school diplomas) are eligible for SSI and other benefits. Most will probably be able to have low paying jobs or will be trained to get moderate income jobs if they can pass a vocational and/or junior college program.
They could be receiving SSDI, and depending upon whose benefit they were beneficiaries of, and how it is calculated, they could each have a fairly decent income, plus additional benefits. If their disability income falls below a certain amount, they would also be entitled to state benefits including Medicaid, food stamps, etc.