I guess this question is related to the Adult Social Care settings. If so, there are some steps to take if consent cannot be readily established.
Ensure they understand and act on an understanding of the health status or condition of the individual. Ensure they understand the individual’s needs and preferences. Ensure they understand the individual’s ability to make decisions. Ensure they have available the relevant information in a form that the person can understand. Ensure they themselves understand the information and options open to the individual. Listen to the person and observe for other responses.