Again, you're repeating yourself here. This is the transitional time. His children are allowed to help their father, and that's constituted because it's a part of his Presidency campaign.

But he is not vested to appoint any of his family members to certain positions in government, including the Cabinet.

In response to that, Congress passed a law in 1967 that prohibits federal officials from appointing family members to certain positions in government, including the Cabinet. So, no, TRUMP cannot appoint a family member to the Cabinet. It's written in our constitution.

NOTE: I'm just saying this as an American (not as Trump's or Hillary's supporter). My point of view is whoever won the Election, that person won it fair and square. It's time to put our differences aside and do what we should do best for the benefits of our country.