Sibling Buyout, Gift Tax, & Capital Gains Tax

My sibling and I inherited our mothers home after she passed away and we decided to do a sibling buyout. He bought me out for less than fair market value of the property and he is keeping the home to live in with his family. If property was valued at a little over $1M, and I was bought out at $200K, am I subject to pay a gift tax or is my sibling? Also, am I subject to pay capital gains tax?