What to do when a manager is useless at their job (to the point where it’s effecting the people working under them)

I’m only asking now because up until today, I was fine with just nodding along with the annoying, circular conversations about ‘inspiring greatness within the staff’ (it’s a retail location sir). But now I’m seeing the actual issues with this guy and it sucks

For context: I had to step in today on a conversation between him and an upset customer who was trying to order a custom cake (because for whatever reason catering doesn’t communicate any basic information about what they handle to us, but also leave early so people can’t place catering orders in person after typical working 9-5 hours).

He’s training to be a manager, but the way he was talking to this woman came off as so condescending, and like he thought it was all just a joke, when this lady just wanted to know portion sizes and prices for sheet cakes. He even had the audacity to say he didn’t know that information without attempting to find it first, and offered her everything but a solution to the actual problem, which obviously pissed the customer off more

I found that basic information for price and servings for the cakes on our store website in 5 minutes, and was able to give the woman the information. I stepped in and gave her that information, because that was the way to de-escalate the situation properly. I’m a customer service rep, I shouldn’t have to de-escalate situations with customers for a manager.l because he refused to take his phone out and look up the info himself.

She still left slightly unsatisfied with the answers, mainly because she felt like she’d been led on this huge chase to get basic answers, which this manager denied to her face, by saying he did give her the answers

On top of that this guy doesn’t seem to understand what the job of a store manager is, he refuses to learn how to operate a cash register (because helping with checking people out at a till isn’t the job of a store manager), he gets into arguments with employees (meaning I don’t feel safe telling him no or that something isn’t possible if he’s putting strain on the front end by taking our already limited staff to do other tasks in other departments), and it’s clear he doesn’t have retail/managerial experience, and just knows the buzzwords to make himself sound like a good manager (nobody knows this guy’s work background prior to the job he has with us, all we know is he originally lied about his age, and said he was younger than he actually is)

Idk what I should do if anything, because this bullshit is going to end up leading to the Front End/ Customer Service dealing with more and more angry customers who feel like they’ve been patronized to by a manager instead of having their concerns taken seriously, and it’s putting all of the customer service reps/ head cashiers (especially on night shift when he’s closing and our direct front manager is not in) on edge because we see how unserious about it all that he is.

I only stepped in to de escalate, but now I’m terrified that I’m more competent at a managers job than the actual manager that’s supposed to be in charge of the store.