Not quite...Dougherty indicates that in the Son'as' current state simply settling on the planet won't heal them...essentially they need a concentrated burst.
Not excusing some of their actions, just saying that the idea that they can simply settle on the planet and everything will be fine is contradicted earlier in the film.
They could have apologized and returned to the planet 100 or 50 years before the film. They could have also accepted the fact that they simply grow old and die, like any other living being in the universe. They didn't. Instead they chose to take it by force.