Short comic with my sona.
A little bit of world building: They are a shapeshifter that was born from a human woman and then adopted. It wasn't until later that the families found out they weren't human, but because they have a valid birth certificate, adoption papers, a generally human appearance, and two families full of persuasive advocates, the courts decided that snake is legally a person and entitled to all the rights a person has.

They can also be considered human based on some technicalities (Species can be defined as a group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring. Which Snake is definitely capable of. However that definition already has some issues especially when trying to apply it to organisms that reproduce asexually before you factor in the fact that snake is technically capable of producing fertile offspring with just about any organism.)

Suffice to say the best term for snake is "more than human"