These papers on general guidelines are publicly available.  Click on the citations to view the articles.

Abeles, N. (2014, May). What mental health providers should know about working with older adults. American Psychological Association. https://www.apa.org/pi/aging/resources/guides/practitioners-should-know

American Psychological Association (2014).  Guidelines for psychological practice with older adults.

American Psychological Association (2012). Guidelines for the Evaluation of Dementia and Age-Related Cognitive Change. American Psychologist, 67, No. 1, 1–9.

The National Consensus Project for Quality Palliative Care.  (2013).  Clinical Practice Guidelines for Quality Palliative Care, 3rd edition.

Previous version of Guidelines for psychological practice with older adults: American Psychological Association. (2004). Guidelines for psychological practice with older adults. American Psychologist, 59(4), 236-260. doi: 10.1037/0003-066X.59.4.236

Also available:

Abdulla, A., Bone, M., Adams, N., Elliott, A.M., Jones, D., Knaggs, R., Martin, D., Sampson, E.L., & Schofield, P. (2013).  Evidence-based clinical practice guidelines on management of pain in older people. Age Ageing, 42 (2), 151-153.  doi: 10.1093/ageing/afs199.

Karel, M. J., Gatz, M. & Smyer, M. A. (2012). Aging and mental health in the decade ahead: What psychologists need to know. American Psychologist, 67, 184-198.

Molilnari, V., Karel, M., Jones, S., Sr., Zeiss, A., Cooley, S. G., Wray, L., Brown, E., & Gallagher-Thompson, D. (2003). Recommendations about the knowledge and skills required of psychologists working with older adults. Professional Psychology: Research and Practice, 34(4), 435-443. https://doi.org/10.1037/0735-7028.34.4.435