Those who find the ending to be uplifting and heartwarming point to the fact that it brings the two main characters, Raymond and Charlie, closer together. At the beginning of the film, Raymond is depicted as being almost emotionally unreachable, while Charlie is self-centered and preoccupied with his own problems. However, by the end of the film, they have formed a genuine and lasting bond, and Charlie has come to appreciate his brother's unique gifts. Additionally, Raymond is able to find a measure of peace and happiness in the group home where he is placed.
Those who find the ending to be bittersweet or depressing, on the other hand, point to the fact that it is unclear whether this newfound bond will be enough to sustain Raymond and Charlie in the long run. Raymond still struggles with his autism and will likely always need some level of care, while Charlie has a busy and demanding life that may make it difficult for him to spend a lot of time with his brother. Additionally, the group home where Raymond is placed is depicted as being a rather sterile and impersonal environment.
Ultimately, the ending of Rain Man is a matter of personal interpretation, and there is no one right or wrong answer. However, it is undoubtedly a thought-provoking and emotionally powerful ending that leaves a lasting impression on viewers.