Federated Learning (FL) facilitates collaborative model training across distributed clients while ensuring data privacy. Traditionally, FL relies on a centralized server to coordinate learning, which creates bottlenecks and a single point of failure. Decentralized FL architectures eliminate the need for a central server and can operate in either synchronous or asynchronous modes. Synchronous FL requires all clients to compute updates and wait for one another before aggregation, guaranteeing consistency but often suffering from delays due to slower participants. Asynchronous FL addresses this by allowing clients to update independently, offering better scalability and responsiveness in heterogeneous environments. Our research develops an asynchronous decentralized FL approach in two progressive phases. (a) In Phase 1, we develop an asynchronous FL framework that enables clients to learn and update independently, removing the need for strict synchronization. (b) In Phase 2, we extend this framework with fault tolerance mechanisms to handle client failures and message drops, ensuring robust performance even under unpredictable conditions. As a central contribution, we propose Client-Confident Convergence and Client-Responsive Termination novel techniques that provide each client with the ability to autonomously determine appropriate termination points. These methods ensure that all active clients conclude meaningfully and efficiently, maintaining reliable convergence despite the challenges of asynchronous communication and faults.