Start your search with the official agencies. You know them better than I do because you're already working with them. Talk to the people involved with providing financing for families and children with disabilities. Do they know of any grants, any special funding? Then talk to whoever else helps these people with special needs, whether it's school district or county government or whatever.
Always, as you make these calls, brace yourself for the person you're talking to not to know, not to have a good answer. As soon as it comes to that, always ask that person who else might know. Never end a phone call without asking who else might know.
You should also do an internet search starting with www.sba.gov, the main Small Business Administration website. There are some special facilities for minority owners, but you have to go through the details. And, for the record, SBA loans are managed by local banks.
What I want to recommend most is that you be very skeptical of people charging you money to help you get your grant. Some of these people are for real--many aren't. If you do work with somebody like that--and I don't blame you for wanting that--make sure you first check with references, especially past clients.
Good luck with it,