E'Syious looks like a phonetic version of Esais, a spanish form of Isaiah
. The whole thing could be meant to be like one of those long descriptive spanish religious names like Maria-de-los-Angeles, Maria-de-la-Paz, Maria-de-Monserrat in this case Esais-del-monte "Isaiah
of the mountain". It's an inspirational sounding name. Your son's biological mother may only have seen him once but she left him with something unique and something to be proud of. If she hadn't cared she wouldn't have taken such particular trouble. That's a treasure in itself.