From the FamilySearch.org site.1880 census Hunt Co, TX:
Category: Name;Relationship to head of household; Marital Status; Gender; Race; Age; Birthplace; Occupation; Father's Birthplace; Mother's Birthplace.
Ge. W. PEMBERTONSelfMMaleW40MOFarmerMOMO Mary E. PEMBERTONWifeMFemaleW32ARKeeping HouseARAR W. T. PEMBERTONSonSMaleW12ARWorks On FarmNCNC O. C. PEMBERTONDauSFemaleW9TXMOAR Robert L. PEMBERTONSonSMaleW6TXMOAR Nancy E. PEMBERTONDauSFemaleW1TXMOAR
Looks like Robert's sister married a Muse.1900 census Hunt Co, TX:
Muse, Joseph T., h, b Jul 1872, 27, M 5 yrs, b TN, TN, TN " Bettie, w, b Aug 1878, 21, M 5 yrs, 2 ch, 2 lvg, b TX, MO, AR " Opal, d, b Aug 1896, 3, b X " Lillie, d, b Dec 1897, 2, b TX Pemberton, Mary, m-in-law, b Oct 1847, wid, 5 ch, 4 lvg, b AR, SC, TN [Bettie is probably Nancy E. and E. is probably Elizabeth.Note she shows her father born MO.]
1910 census shows Mary still living with family.By 1920 Mary has apparently died and Joseph is a widow, so Bettie has died, too.Joseph is living with his married daughter, who has married Herbert Stewart.You might try to track down descendants in this Muse and Stewart line.See if they know something that will help you.
On the 1870 census George shows he owns land $1100, I would look for guardianship records for his minor children.Yes, even though the mother was living the court would appoint a guardian to just report back if any of the estate was sold, to protect the interests ofminor children.By 1899 the court may have "allowed" the mother to be that guardian.I have one in 1889 in Wilbarger Co, TX who petitioned the court and they allowed her to be the guardian for her children.
Also, I would look through court records.George has quite a bit of wealth for one who fought in the Civil War and has young family.Did he inherit?If say his father lived elsewhere and died, George might have given power of attorney to someone back where his father died to collect his share of that estate.That would be recorded in the county where George lived, the clerk would verify who George was, then send it on to be recorded where estate was probated.I tied 7 of 8 siblings through just such records.Siblings lived in NC and KY and their unmarried brother died in OH.