Mr. Harrigan's Phone (2022) on Netflix

When Mr. Harrigan dies, the teen who befriended and did odd jobs for him, puts his smart phone in his pocket before burial and when the lonely youth leaves his dead friend a message, he is shocked to get a return text.

Craig, a young boy living in a small town, who befriends older, reclusive billionaire, Mr. Harrigan. The two form a bond over books and an iPhone, but when the man passes away, the boy discovers that not everything dead is gone, and finds himself able to communicate with his friend from the grave through the iPhone that was buried with him.