I had several classes during the evening from 5-9 or 6-9 pm. I either brought an extra sandwich or sub with me, or left-overs from dinner. The professors didn't care if people ate during the classes because at that time of the day it's understandable, as long as there wasn't a lot of loud crumpling while the lecture was still going on. Sometimes they would take longer to give the breaks and my stomach would growl, so I'd just eat right then and there.

I assume you're going to UofT, so if you haven't taken a stroll through there, you should because it's a maze. See how far your lecture halls are from cafeterias and if they're too far, then pack some extra food. I know a sandwich or sub isn't that fabulous for dinner but it's what you gotta do. Some days I had noodles with tomato meat sauce and garlic bread, other days just a plain sandwich.

In my last years, I did a lot of research in labs and again I brought food, however, I would eat outside the lab before it began. For several labs, we had to come in at our own time in addition to the scheduled time, so I'd be sure to have a large meal before then. Each time you leave the lab though, make sure your take off your gloves, mask, and anything else, although no need to take off the lab coat.

If you're already doing part-time paid teaching, then I don't see why your brother would want you to get another job.