Zio Eliseo is like a Bach composition that's taken human form: he's a classic and will remain so until the end of time. (Think the Cello Suites more than Toccata and Fugue in D Minor. That last one is way too vampire.)
The maître d' of a local hotel, Eliseo is a man interested in everything life has to offer him. How can we tell? Just look at the stuff he keeps in his storage house: everything from books to art to this newfangled thing called a bike.
Not that those things will ever catch on, but he gave the hobby a go, at least.
When he's not helping people at the hotel, Eliseo's role is to be a mentor figure to his nephew, Guido. When Guido takes a job as a waiter, he isn't too good. Like at all. He can't remember how to serve lobster or wait on guests or how low to bow. This last one forces Eliseo to bust out a lesson on what it means to serve others:
ELISEO: Think of a sunflower. They bow to the sun. But if you see some that are too bowed down, it means they're dead! You're serving. You're not a servant. Serving is a supreme art.
This nicely sums up Eliseo's philosophy of life. He's not there to be a servant to others (i.e., to see himself as less than they are). Instead, he's there to help his brothers and sisters in humanity, to make their lives better or easier or more fruitful in whatever way he can.
Unfortunately, this kind old man is also the victim of anti-Jewish prejudices. Twice, we see him attacked by "barbarians" who beat him up simply because he's Jewish. This leads him to give Guido a second life lesson: "You'll have to get used to it, Guido. They'll start with you, too."
Guido brushes these sagacious words aside, but they prove prophetic later in the film when Guido, Joshua, and Eliseo are taken from their home to be sent to a concentration camp.
At the camp, Eliseo's pulled aside to be executed in the gas chamber along with the other elderly arrivals. On the way, a woman guard trips in front of him. Without a word or second thought, Eliseo offers to help her up.
It's a small, but powerful gesture. Despite all that the Nazis have done to him, Eliseo tries to help one of them, staying true to his philosophy. Not because he is a servant, but because he's a human being and feels the need to help a fellow human being.
In return, she stares at him with contempt.
Although she may not have appreciated it, we sure did. A man's got to have a code, and Eliseo stuck by his until the very end.