All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
Know that your brothers are not Mahaarim for your wife, and they are like all other non-Mahram men. So, she should not uncover any part of her body to them.
For more benefit on the evidence for Hijaab and its conditions, please refer to Fataawa 81554, 83765, 83702, 81494, 354259, 83033 and 82977.
As for your father, he is a Mahram for your wife, so he can see from your wife what is permissible for Mahaarim; i.e., head, hands and feet according to the most correct opinion of Muslim scholars.
Allah knows best.