Yes, a job in high school is definitely something that college admissions officers look favorably on. Less thatn half of high school students in the U.S. have a job so this will mkae you stand out. It shows responsibility and dedication and is considered as important as a team captain or student government officer by admissions offices.
To help family, I'm working a lot of hours so it doesn't leave any time for extracurricular activities. I'm thinking about keeping this job during the week and doing a second job over the weekend. If one job is a good resume builder, would two jobs be better?
The key here that will catch the attention of college admissions offices is that you are working to help your family. If you are working full time during the week, working part time during the weekend is another thing to add to your resume. If you need to do this to help your family, that is admirable. If you get a second job for your resume, it is not better to have two jobs than one job. What is important is that you are working full time to help your family. You don't want to get worn out by working all weeke with no time off to relax.