Advarius Furystrykar has a sister, Lieutenant Blair and something Sims 3 has, but Sims 4 hasn't got.

 Turns out that Rachel Applebee is Advarius Furystrykar's sister.

 This is her new bedroom in the Furystrykar residence

 I also made a dedicated room for the skill certificates

 Rachel Applebee helps Drake Furystrykar with his homework.

On the left, Rachel's Jamboree and on the right, Blair's Police Cruiser.