Franco is a good times guy. He went to high school with Santiago and dropped out the same time he did to go work with his dad as a plumber. Franco was born in California to illegal immigrants, but subsequently is a citizen.
Prior to going to work with his dad, he started getting in trouble at school and with the cops for stealing, loitering and graffiti. He was never caught for most of what he did, but a few years into his work as a plumber, he was called into court where he had a choice of jail or military service. He ended up going to Iraq for 27 months.
He returned with PTSD and was mostly dysfunctional and incapable of keeping a job. Santiago got him work as the maintenance guy at "O'Neils" and he lives at Santi's house during this time of healing.