The term "geriatric" is basically an offensive term when applied to older persons. As well as many other terms such as elderly, geezer, old timer, etc. There seems to be few words with a positive slant in English that I am aware to refer to older persons although "venerable" has a positive connotation. Fortunately the Thais/Asians don't seem to have negative feelings toward older people and treat them with the respect they deserve.