Pompey can not estabilish a real dynasty, he has neither the blood, the support or the interest to do it... He only wanted to be recognized as the uncontested Primus inter Pares, so is not unlikely who if Caesar is already a close ally, likely his right hand and a relative by marriage will be able to essentially take over after his death... Gaius and Sextus maybe will not be happy about this but they will still have a big part of their father's fortune and with that a lot of political power, clientes, resource and influence so they will likely stay satisfied.