Special Needs Trusts can be funded by a will, family/friends, gifts, and life insurance. Lawsuits are best held in a "self settled trust." This trust will avoid Medicaid ineligibility.
While monthly SSI benefits can be spent on the necessities of life, such as food, shelter, etc., the special needs trust money can be spent of items that give the disabled a bit more joy and a better quality of life. Eventually, the special needs trust can spend funds on funeral/burial costs. The trustee can be anyone that is a trusted individual, such as another relative, your pastor, friend, etc. as long as they are willing to follow your intent for the recipient. Some choose a financial institution or legal entity to dispense monies as needed; however, expect a modest fee.