People with disabilities have a legal entitlement to a so-called "personal budget", which is paid to them instead of service or in kind. This allows them to independently finance benefits that they need for daily help, and thus make their own lives. Parents of disabled children are also entitled to a personal budget. It can be used, for example, for individual help, social assistance from the youth welfare office or holiday care from the youth welfare office.
Children with disabilities may be eligible for integration assistance. In Hamburg, the social services are responsible for advice and approval: http://www.hamburg.de/kinder-familie/2219894/hilfen/
Information can also be found at: https://www.elternimnetz.de/kinder/sorgenkinder/hilfen.php