In this case the class teacher of your child is the first contact person. Parents, together with the school should consider which help can be offered, which measures are meaningful.
Support is also available from the School Psychology Service in Sachsen (https://www.bildung.sachsen.de/1278.htm).
Pupils from families who get help for living can get benefits for learning support from the education and participation package (https://amt24.sachsen.de/leistung/-/sbw/Bildungspaket+Leistungen+fuer+Bildung+und+Teilhabe+beantragen+Empfaenger+von+Arbeitslosengeld+II+und+Sozialgeld-6000905-leistung-0).