I have a project manager that's been very relaxed on actually managing a project. His main style of management is to pick a laundry list of things that need to be accomplished in 1 week and tell the dev team to figure out a way among ourselves to complete everything. No prioritization, no assurance that everything's being completed, and this leaves more experienced devs directing junior devs ourselves because they don't know enough to self prioritize.
A meeting was scheduled over the weekend with the client to hammer out a pretty key part of a project, how a 3rd party api being built by another team would interact with our own. My manager has access to my calendar and accepted this meeting but I can see his and he plans on being else where. The other devs are also not going to the meeting. While I am very happy I'm trusted to go solo I don't think it's a good idea for me career wise.
More so, this other team is an in house dev team for the client while we are an outside contractor so it's almost a given that if they want to go in a certain direction the client is going to lean in that direction.
I simply don't have the authority to tell the client to back down on a feature request or how long something might take. I can tell them how long a feature would take, but given that I can't say if we'll even do it, I can't give an answer on time. More importantly, without the manager there I am left constantly telling the client "I'll need to discuss that with my boss" which can't be something they're going to want to hear. I know if I were them I'd wonder why I was there without someone who could actually make decisions, so I feel like I'm being setup to leave a very poor taste in this clients mouth and look like a glorified note taker.
How do I tell my manager I shouldn't be going to the meeting without him or in other words I'm not going to do his job for him?