Whenever someone tells me that the end is near, I ask the person one question:
"If you focus on the fact that the end is near and you are thinking mainly about a reward from God, is in fact you support the reasoning of Satan, which says that a person (for example, Job) serves God only for the benefits?"
It is a question enough biblical and innocent at the same time, you can ask them freely, even forcing someone to think and not fearing that you'll be accused of apostasy.