Elderly care becomes more and more important as elderly populations increase. Many solutions are proposed for monitoring elderly activities of daily living (ADL) or healthcare related data. There are two aspects to be tackled to enable monitoring for elderly care. On the one hand, the up-to-date ADL sensors and biosensors greatly facilitate collection of various ADL and healthcare related data. On the other hand, data captured by sensors need to be gathered from residences of elderly people to local community center for monitoring and analysis. Therefore, gathering sensor data plays a significant role for building elderly care systems or architectures. Most current elderly care systems or architectures are developed based on reliable network infrastructures. However, such presumption is less practical in network deficient environments such as geographically depopulated rural and remote areas. In this paper, we propose a data gathering system model for elderly care based on autonomous device-to-device (D2D) communications, which is self-contained and independent from other network infrastructures. The proposed system model doesn’t need central control; thus, it can be simply deployed in network deficient environments or for users without access to existing networks. The idea behind is to use ad hoc D2D links by introducing moving devices. Procedures of data gathering using D2D are proposed and configured by modifying the two-way untargeted discovery protocols of IEEE Std 802.15.8. To examine the feasibility of the proposed system model, a prototype D2D system is developed using off-the-shelf radio modules and ADL sensors. We examine the efficacy of the prototype system through field trials in a mountainous village. Our obtained results confirm the usefulness of the proposed D2D solution for gathering ADL sensor data for elderly care in network deficient environments. Examples of using the gathered ADL data to detect anomalous events are presented.