1)
Was he truly crying?
1.
Radak: He pretended to be crying [Malbim - over an alleged command of Nebuchadnetzar that Gedalyah kill anyone who mourns over Beis Hashem or goes to burn an offering to Hashem there].
2)
Why did he tell them to go to Gedalyah?
1.
Malbim: He wanted people to think that they were killed via Gedalyah's command.