Elio survived many years of perilous Aura training, multiple kidnapping attempts by and confrontations with his natural enemies - the Pokémon Hunters, thrived in the hostile pocket dimensions and alternate realities of Ultra Space - albeit with basic protection, got (un)intentionally caught up in a few life or death situations with little to miraculously no damage to his person due to how well he handled said situations with the then-available tools that were at his disposal, and traversed numerous environments across multiple regions with little to no issue.

I'm 10000% sure he could thrive on a deserted island for a mere 100 days. No cap. Despite appearances, his survival skills are through the roof via his aforementioned experiences. It's one of the perks of being globetrotting trainer :)