In the mother's defense she doesn't have the same perspective as him.
To him losing is a big event for him and his life and career, to his mother he fell down and now he gotta get up, maybe that's how she sees it.
Also she is from North Phili, maybe the thought of losing the house was a reminder of poorer life she had.
For him, losing was a significant personal and professional setback. For his mother, it might have been another instance of life's hardships and an acknowledgment of what a boxing career entails from the perspective of someone outside the ring.
Sometimes you lose a fight.