Is Incognito Really Private?

[Merie]

So i go on Incognito a lot (I don't do anything bad). I don't like the history being stored & all that. I read Fan fictions, i go on Facebook, Twitter, & that's all. I was on Facebook the other day (Incognito) My "Step-Dad" Said, "She's on private again" & before he has said, "Incognito doesn't make your things private". Could he be trying to scare me? Or could he be watching what i was doing from his iPhone or laptop? He seem's to only confront me when he is on his phone or laptop. & he has access to everything. But, i honestly doubt he has a key logger thing. I use Google. Help?