From what I've read, diesel generators are very inefficient. And from a security standpoint could stand to make it more likely that you will get busted for having a generator running in your backyard 24/7 (12/12, even).

As mentioned earlier, I would suggest he set aside a space for when he goes to max out his grow ops. Then, start with one or two lights. Then, develop a system of either hydroponic or soil. Don't worry which one. I suggest starting with soil if it's your first grow and move to a small hydro setup after one or two harvests. Then, look at expanding your operations.

Just you and your brother watch your asses if you get a big grow going.

If it is his goal to use 1000W lights, then he should start with one and grow a few plants at a time. Or, get a 400W light and grow one, maybe 2 plants to start. Once you get the hang of it, a quarter pound off a 400W light is easy.