Following the collapse of the Confederacy and the surrender of the remaining Texas forces, Robertson returned to his home in Independence and resumed his medical practice, a period marked by mourning when his wife died in 1868.
Efter konføderationens sammenbrud og overgivelsen af de resterende styrker i Texas vendte Robertson tilbage til sit hjem i Independence, Texas og genoptog sin medicinske praksis i en periode med sorg, efter at hans kone døde i 1868.