I was able to get every thing with the step dad and the brother except the "make up" part ... how to get to that please ?
Start the Family Union quest.
After the talk with your dad, you can engage in a regular sexual act with either of them while the other is at home. After you've done that, the other will confront you and act jealous, you then will be able to "make it up" to them by either a blowjob or anal. Thus, unlocking these scenes.