Nadler has held the top Democratic job on the Judiciary panel since 2019 and has served in Congress since 1992. He has had some health scares in recent years but was easily re-elected last month.
Vulnerable people with care needs are living in "beyond disgraceful" homes because the government has so far failed to enforce a new law, MPs and charities claim.
Attorney General Ken Paxton sought to delay legal proceedings until Jan. 13 - the day before the committee disbands - even as lawmakers vowed to continue fighting to hear from Robert Roberson.