Yes, there is some really great work that's done by Rachel McNally at Carleton on people with disabilities in displacement contexts. UNHCR also has policies particularly on disabled people in displacement contexts.
In some cases, as you mentioned, there's an intersection between age and disability. Older people might also be disabled, and there are some policies on that in terms of the older people. HelpAge and UNHCR have specific guidelines on older people that also include issues around disability.