Minors in self-employment

Brother and sister age 16 and 14 have been given livestock from retired grandparents. Brother and sister now farming the animals using their own resources (ie own time and own capital). Parents occasionally help (eg driving). Also some of the paperwork has to include one of the parents for legal reasons eg Single Farm Payment claim. All paperwork will revert to brother and sister as soon as they cease to be minors. There is no doubt the brother and sister are genuinely running the business. Parents are dependant on state benefits eg tax credits, child benefit etc. Will the children’s self-employment have any negative impact on parents’ state benefits?