While I didn’t find anything that specifically answers your questions, I found a few things that may be helpful in your search.
1930 US Census, enumerated 4/17/30 – at#400 N. Texas Ave, Mercedes, Hidalgo County, TX shows Leopoldo Solis (age 26) his wife Manuela (age 22) and son Leopoldo (age 9/12).Leopoldo Sr was listed as a salesman, retail grocery.Interestingly, all three were listed as born in Texas.Perhaps an error or, the other possibility is they were born in Texas and their parents came from Mexico.
In the same census, immediately before them, at #399 N. Texas Ave:
Torinio Solis, age 69, barber Erlinda Solis, age 59, wife Emelio Solis, age 35, son, carpenter Cilia Solis, age 30, daughter Jose Solis,age 19, son Felicitas Solis, age 15, daughter
The parents listed in this family were born in Mexico, listed as immigrated in 1909.The children were all born in Texas.Given they lived in such close proximity to Leopoldo and Manuela, perhaps they were some sort of relations to your family?
The Texas Death Index lists Leopoldo Solis as having died in Cameron County 2 October 1991.The Social Security Death Index has the same death date but also lists a birth date of 20 Feb 1904.
From Harlingen, TX directories:
1952 – L. Solis (Manuela), lab, res Avondale Add’n 1954-Leopoldo (Manuela) Solis, mech, res La Paloma Ave Also listed was Leopoldo Solis, college student, same address 1956-Leopoldo (Manuela) Solis, mech Cox Motor Co, res 1802 La Paloma Ave Rt 4 1956-Leopoldo (Corina) Solis, tchr Harlingen Schools, res 312 W McKinley.Corina was also shown as a teacher
In 1956 a Noel Solis was shown as a college student living at 1802 La Paloma Ave Rt 4.I note that Shelly found an obituary for someone by this name.Since he was apparently living with Leopoldo and Manuela in 1956, perhaps he is some sort of relative.