That is presuming the guy was correct about being saved and was actually saved in the first place.
I have been backslidden at least for one period of time...God may deal with that fella as he did with me...In which case, he'll be back...
It's easy actually, to, just for a moment, convince yourself that God doesn't exist...But if one knows a little bit of bible prophecy, he can't look at the world right now and honestly say God does not exist...
I don't put much stock into what so called atheists claim...If a Christian does turn from God, just as the prodigal son did, God may beat him and whip him into submission, all the way HOME...
Every time a person disobeys legitimate authority, they sin, ergo they turn away from God and His Plan.
That also means that when God allows a Satanist to be placed in political office as a leader of a nation, we are to obey through faith in Christ.
Part of this reason is that we are engaged in spiritual warfare and our allegiance is to God through faith in Christ. We bare our Cross daily in these times, not by living to perform good or avoid evil, but by living through faith in Him.