Oh there is no doubt that he is safe for re-election unless he votes for the wrong things.At this point it is not reasonable to expect WV to do anything but re-elect Senator Manchin by a very large margin. I would go so far as to say that it would be downright stupid for democrats to do anything but have him go unopposed in the primary.
He is an excellent spokesman for the moderate wing of the democratic party, and is getting himself set up to be the conservative spokesman for the whole country should the republican party implode. Trump has ruined any republicans that are not 100% submissive to him, and should the republicans implode all the remaining republicans will go down with the Trump ship. Senator McConnell was their best shot of returning to normalcy, but he has been marginalized so badly that he can't do it anymore.
Conservatives leaving the republican party may very well find that moving the democratic party to the right in tandem with Senator Manchin might very well be their best shot at maintaining some semblance of power and influence moving forward. Apparently the business community is throwing their lot in with Senator Manchin, and no doubt many others will take notice.
From what I have seen, Senator Manchin is definitely up to the task of becoming a national leader. If circumstances break right for him, he could become one of the most powerful people in the US.