Like Taylor said quarantine will be of utmost importance.
Also be prepared for vet bills if the snake has been poorly cared for.
Have you seen pictures? It would be nice to at least be able to ID the snake before agreeing to take it. "Brazilian Python" leaves lots of possibilities on that table. I wouldn't assume BRB just because they said "Brazilian". They clearly don't know what they have, so I'd say almost any boa or python species is a possibility.