<p>The enormous growth in the development of smart healthcare services has increased the need for protective, secure, low-latency, and scalable infrastructure capabilities to support heterogeneous devices and continuous clinical processes. In order to provide smooth communication between mobile, wireless, fog, and cloud nodes, this article offers DBH-Chain, a lightweight, decentralized blockchain-enabled healthcare system that mainly uses a client-to-fog and fog-to-cloud socket architecture. To address the hybrid intercommunication and processing delays among the nodes of the heterogeneous layers, the research creates a queuing-based Mobile Measurement Partner (MMP) hierarchy in conjunction with a Knapsack-driven adaptive scheduling algorithm and Markov Modulated Poisson Stream (MMPS). Strict latency limits and effective task execution are made possible by this design technique. For creating security and trustworthiness, in order to address lightweight computation, this research propose a Proof of Validation (PoV) consensus that guarantees authenticated interactions among the participating distributed nodes. In comparison to other cutting-edge healthcare architectures, the results of the simulation show that the proposed DBH-Chain achieves up to 99.32% scheduling efficiency, a reduction in hybrid delay down to 41% to 57% and maintains the data validation integrity in the ledger up to 98.87%. However, the report of comprehensive analysis confirmed that the proposed solution significantly reduces end-to-end latency, strengthens data security, and improves workload distributions. In short, it provides a robust and practical foundation for futuristic smart healthcare systems.</p>