FieldValueList c = qr.getValues().iterator().next();
c.get("family").getRepeatedValue().get(0).getRecordValue().get("id");

Method threw 'java.lang.UnsupportedOperationException' exception.
Retrieving field value by name is not supported when there is no fields schema provided

qr.getSchema().getFields().get("family").getSubFields().toString();
-->
[Field{name=id, type=INTEGER, mode=NULLABLE, description=null}, Field{name=name, type=STRING, mode=NULLABLE, description=null}]

c.get("family").getRepeatedValue().get(0).getRecordValue().get(0).getLongValue();