TOPIC: PMP Question? Looking for answer

Project Manager is in project closure phase. If Client is unable to do payment settlement, due to internal issues going in his organisation, and its resolution might take around 2-3 months, then can Project Manager formally close the Project with this as known risk or can he help client in assisting him figuring out internal issues in client organisation to make it a speedy process or he needs to just notify sponsor and wait for claim settlement before he can formally close the project?

Expert inputs needed!