Why did sundiata not walk after recieveing his mother and treatments but did walk when his half brother was made king?

Sundiata did not walk initially due to being afflicted with physical disabilities. Once his half-brother assumed the throne, he was inspired to walk as a symbolic demonstration of his regained strength and determination to fulfill his destiny as a future leader. This act also proved his readiness to assume responsibilities and support his half-brother as the new king.