In 1985, "health-care entrepreneur Miguel Recarey Jr. hired" Jeb Bush "to help locate office space in South Florida." Bush later opened doors in Washington, "where Recarey … mounted an aggressive lobbying effort for a waiver from Medicare rules that would allow his fast-growing company to continue to expand. … [T]wo years later, the firm … was shut down as regulators searched for millions in missing federal funds. … Recarey fled the country to avoid prosecution” and “remains a fugitive in Spain. … Time and again," Bush "benefited from his family name and connections to land a consulting deal or board membership, sometimes doing business with people and companies that would later run afoul of the law." (Washington Post)I have no idea whether Bush's actions in this instance were illegal (I presume not) or even unethical (sounds that way, but we're seeing only one side of the story). In any case, I don't see any likelihood that this will derail Bush's candidacy.
In truth, I consider that candidacy to be already derailed, or more accurately to have had little chance from the beginning. Bush of course seems to have tons of money, which is certainly better than not having tons of money, and there is always the strong possibility that the Republicans will do something stupid, but there seems to be approximately zero support for him among the party's grass-roots (aka the people who vote in primaries and, especially, caucuses), and I doubt that the Republicans (who very much want to win in 2016) will choose to counter a tired name from the past (Hillary Clinton) with … a tired name from the past.