John Thomas Deweese (4 June 1835 – 4 July 1906)
Pvt Co E 24th IN Infantry & Col 4th IN Cavalry. He was brevetted Brig Genl among a large group of brevets backdated to 13 March 1865. His Find-A-Grave memorial states that his brevet was not confirmed until March 3, 1869. In 1868, he was elected to Congress NC (R.) and on March 1, 1870, he was censured by the House of Representatives for selling an appointment to the Naval Academy. He resigned his seat.
Sources: wiki/John_T._Deweese https://www.findagrave.com/memorial/7383777/john-thomas-deweese
Over a 3 hour period I went thru a list of 136 out of 320 Civil War officers appointed to general from March 13, 1865 and after, then looked up the biography of each one. On number 136, my answer, John Thomas Deweese, met the question's criteria:
Brevet Brigadier General
Promoted to rank from March 13, 1865
"He resigned his seat in 1870 when he was censured by the House of Representatives on March 1, 1870, for selling an appointment to the Naval Academy."
Died on July 4, 1906
This officer was the last of the Brevet Brigadier Generals confirmed for Civil War service. After
being censured for accepting a bribe for an academy appointment, he resigned from congress.
He died in the 20th century.
Who is he?
John T. Deweese (1835-1906). He was among the large number of Brevet confirmations March 12, 1866, effective March 13, 1865. As Representative of North Carolina's Fourth Congressional District, he resigned his seat February 28, 1870 and was censured the following day for taking a bribe to appoint a constituent to the United States Naval Academy.
WOW! This question has me baffled. I've spent more time searching than any trivia question to date, and found several persons who fit the criteria on certain issues, specifically corruption, but found none who:
1) died in 20th Century
2) last Brevet Brigadier General confirmed for CW service
3) censured for accepting bribe for academy appointment
4) resigned from Congress
Thanks, @sarladaise. I learned a lot, however, things like how U.S. government bodies are getting more and more lax about calling out its criminals of certain stripe and hue.
Then, another thought came. Was a man, during the CW, who paid someone else to go to war in his place committing a type of bribery?
I am not sure there is an answer. According to House.gov 3 members were censured for selling appointments in 1870. Benjamin Whittemore (1824-1894) was a chaplain with the Fifty-third Regiment, Massachusetts Volunteers and Thirtieth Regiment, Veteran Volunteers. John T. DeWeese (1835-1906) was a lieutenant colonel in the Fourth Indiana Cavalry. Roderick R. Butler (1827-1902) was a lieutenant colonel in the 13th Regiment Tennessee Volunteer Cavalry. There was a Thomas Harvey Butler (1833-1912) of the 5th Regt. Indiana Volunteer Cavalry who was Brevet Brigadier General, but did not serve in Congress.
Edit - Can't give you credit, since you didn't indicate which one of the names you listed was your answer to the question.