A recent review examined how convincing the evidence is for the efficacy of various Complementary and Alternative Medicine procedures in late-life mood and cognitive disorders, including Alzheimer's Disease (AD).
In the specific example of coconut oil it concluded that: "
Therefore, the use of coconut oil is not recommended for those suffering from AD due to a risk benefit ratio in which the potential benefit does not outweigh the risks of the intervention."
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4110105/