Would the average Singaporean Chinese Mandarin really be this bad?

Hey all I have a serious question that I am trying to rack my brain around. My friend is in the third stage of an interview with a tech company. The job is 90% English speaking. However sometimes they have to deal with clients/customers based in China. Therefore this stage is a mock presentation in mandarin. The brief says they don’t expect native speaker mandarin, just enough to present to the client, persuade them, assure them and answer their questions. 30 minutes. My friend is saying they are 100% sure they will fail even tho they are Chinese Singaporean. Here is what I struggle to understand. I have a non English mother tongue which I only learnt once a week on Saturdays + from speaking with my family at home. I would fail this kind of interview in my mother tongue, but when I look at my friends experience as a Singaporean Chinese: - 5 days a week of Chinese language lessons exposure throughout every year of schooling in Singapore. - Regular interactions with people who can’t speak English in Singapore only mandarin. - Their family is Chinese speaking. When I go to their events they don’t even speak English around me (understand this is not the average Singapore Chinese experience but yeah). - Chinese text seen on a regular basis around Singapore. - Chinese media is quite common and available. For example hearing it on the radio in a random grab ride. If I had this kind of exposure to my mother tongue I feel like i would be a black belt master in it. So what is the challenge Singaporeans feel about speaking mandarin at this level? Help me understand.