There’s no reason that members should be taking contributions from industries they regulate as members of a committee. Nor should they be on one that pays an immediate family member. Evan Bayh’s wife went around soliciting participation on boards of businesses regulated by the Senate Banking Committee when her husband was appointed. Family members are one of the principal ways that cash finds its way into the pockets of members of Congress (Tom DeLay, Tom Daschle, Chris Dodd, etc. etc.)
If a member of Congress feels the need to take donations from a particular industry, or if their family member feels a strong need to do so, the member should resign from the committee and find a different one. There are plenty of ways to serve that don’t involve such conflicts of interest.