What percent growth should I expect a well-run Wealth Management fund to bring, for an elderly person focused on maintaining, over the last few years?

I'm going to attend a meeting my elderly mother will have next week with a boutique wealth management firm. The amount managed is in the mid-to-high 6 figures and it's what my dad left when he passed 12 years ago, and it's been with that firm since then (or with the individual advisor, who left a larger outfit to open his own office). I want to advise my mother, and I just want to make sure the growth is in the right ballpark, and I don't know where to find the expected figures. Many thanks for your advice.