Britney's family seem to be backing him all the way... so he must have some form of parental skills. I believe they have shown their concern for their daughters mental health with the detox attempt.
Although there have been many stories within the press regarding K-Fed's womanising there's been little to say he was an unresponsable Father. I'm sure we would have heard the stories by now & believe it to be in the best interest of the children to be placed with one of their parents even if it feels as if it's the lesser of two evils.
*unresponsible* or irresponsible, even.