An overview of the benefits for families with disabled children can be found at: https://www.berlin.de/familie/de/informationen/finanzielle-hilfen-fuer-familien-mit-behindertem-kind-231
Children and adolescents who are physically or mentally handicapped or who are threatened with such disability may receive benefits from the integration assistance. (https://www.berlin.de/ba-lichtenberg/auf-einen-blick/buergerservice/familie/artikel.280188.php) Help provide the social and youth offices.
Information can be found in the brochure My child is disabled - these aids are available http://bvkm.de/wp-content/uploads/2016_Mein-Kind-ist-behindert-diese-Hilfen-gibt-es.pdf