I'm not really sure what you're asking here. You say that you don't have time or energy to prep, but then you're asking for advice about how get a 700? If there were a magical shortcut to a 700, everyone would take it, and there would be no need for prep programs.

The way to get a 700 is to study intensively and deliberately. Most students study for a minimum of 2-3 months at 10-15 hrs/week before they hit their full potential. As a very broad rule of thumb, budget 1 week of 10-15 hr studying for every 10-20 points you want to gain. To go from a 500 to a 700, that would be a minimum of 10 weeks, but more realistically 20 weeks of intensive studying.

If you don't have time to commit to studying, then I would recommend that you not take the GMAT this year. Attend to your family problems, and study little by little over the next several months, and aim to take it for applications in 2019. You really won't have any luck trying to cram or rush it, and there are no short cuts.