Is there any setting in Siri which helps in recognizing weak and high pitched voice?

My wife is 80 years old and her voice is weak and Siri I guess cannot understand a week or high-pitched voice and will not answer her at all. She can tell Siri to make a phone call iPhone call to a particular contact and Siri never answers. Is there a way to get Siri to recognize this voice thank you.

[Re-Titled by Moderator]