If an IRS agent shows up at your house, unannounced, that’s a common tactic. They do that all the time because they want to catch you off-guard, unprepared. Take a deep breath. Realize you’re not prepared to talk to these guys. Tell them you’re not prepared. Tell them that you want to talk to them later on.
And then, what you need to do is hire a lawyer, one who knows what they’re doing in this area, one that can protect you and protect your rights. I doubt very much if the IRS agent showed up unannounced because they’re your friends.