On balance, is family a positive or negative force for Hanna, the main character?

This is an "on the one hand,... but on the other hand,..." kind of answer. On the one hand, Hanna always thought her mother hated both her and her father. As a result Hanna has psychological impediments to a fulfilling life. On the other hand, once her father's family makes an entry into Hanna's life, they provide some of the warmth, friendship and opportunity she lacked before. It seems that "on balance," in her third decade of life, her family provides a positive force in Hanna's life.

"He wasn't my patient. Are you mad?" .... [She said in] absolute astonishment, "You thought I didn't love your father?"

To look at Hanna's situation in more detail, despite all the animosity bred from misunderstandings between Hanna and her mother, Sarah, Hanna's early family situation (herself and her mother) allowed Hanna to develop successfully intellectually and in a vein true to her own lights so she became a respected and sought after expert professional. Yet, her deep seated insecurities arising out of her mistaken belief that her mother hated her (essentially because, as Hanna thought, she hated Hanna's father) do obtrude into her professional work as seen in how she falters when she encounters the fake Haggadah and the rejection of her opinion. 

The same misunderstandings between mother and daughter led to Hanna's inability to surrender herself to deep relationships. The late entry of her father's family into her life did do something to assuage that psychological injury, especially after she joins them as a trustee of Aaron's Sharansky Foundation and begins conservation of what her mother called those "meaningless, muddy daubs of primitives." Hearing the truth about her mother and father and being welcomed by Aaron's extensive family do provide the warm embrace of love that Hanna didn't have from Sarah, who infected Hanna with the hostility of her deep guilt and deep sense of loss. With plenty of life left during which to heal, the truth and new warm relationships throw the balance toward family being a positive force for Hanna. 

"I had never, in thirty years, seen my mother cry. I picked up her hand and kissed it, and then I started crying, too."