Chop Shop

Chop Shop tells the story of Alejandro "Ale" (Alejandro Polanco), a 12-year-old Latino street orphan from Queens, New York. The film opens with Ale waiting by a roadside with several other men for work. A man in pickup truck arrives looking for two workers. He tells Ale that he is not needed but Ale jumps into the back of the truck anyway. After realizing that Ale is in the back, he stops the truck and sends Ale on his way with some money for breakfast. Ale spends rest of the day selling chocolate and candy to passengers on trains with his friend Carlos (Carlos Zapata). After they finish selling the candy, Carlos informs Ale that Rob (Rob Sowulski), the owner of an auto repair shop in Willets Point, is looking for new workers.
Ale soon begins working at the repair shop, which Rob has also allowed him to live in. He is soon joined by his sister Isamar ("Izzy", played by Isamar Gonzales) who he finds work for in a food van that sells food to workers on the street. Ale later finds a van being sold by Carlos' uncle that he believes he can fix up and turn into his and Izzy's own food van business. The two begin saving their money to buy the $4,500 van. One night, Ale and Carlos go to the nearby truck stop to see the prostitutes working. There they discover that Isamar is working as a prostitute. Ale is disheartened by the fact but does not confront Isamar about it. The two continue working and saving their money up for the van. Ale makes additional money by selling unlicensed DVDs, selling hubcaps he steals from cars parked at the nearby stadium, and working for another auto shop owner, Ahmad (Ahmad Razvi) by stripping down a stolen car.
One day, after hearing his sister talk on the phone to what he believes is a prostitution customer or a boyfriend, he steals some money from his sister and, together with the money they have saved, buys the van from Carlos' uncle. When he gets Ahmad to look into the repair of the van, however, he is informed that the interior of the van is unfit to serve food off and would cost around $10,000 to fix up. Angry that Carlos' uncle ripped him off, Ale starts a fight with Carlos before getting pulled off. With his dreams crushed, Ale goes to the stadium and snatches a woman's handbag and gets a phone he fails to sell. Isamar questions him about the phone. He yells at her and demands that she "should be working," meaning she should be selling herself as a prostitute to make money for them. Isamar realizes her brother knows about her secret. Ale decides to get the van stripped for parts and loses money.
Ale has nothing left. His dreams and his life have been "chopped up" into parts. He goes to the truck stop to look for Isamar. There, he begins to attack the man receiving a blowjob from his sister, before the two of them run back to the auto shop. When they get there, Isamar hides in the toilet and doesn't speak to Ale. The film ends the next day with Ale feeding seeds to the area's pigeons to cheer her up. The pigeons' sudden arrival make Isamar smile with her brother. She then scares them away and they go flying up into the sky.

Question: Ale discovers that Isamar is working as what to make money?
Answer: A prostiute