Is this possible to drop an author from authors' list of a paper after revision?
Is this possible to drop an author from authors' list of a paper after revision?


Perhaps, but very very unusual. This should really never happen - the only case I can see reasonable is if someone was included as an author but either found their own contributions to be insufficient or disagreed with the publication and requested that they be removed from the list. It should definitely never happen when that person has a legitimate claim to authorship.


  What are my options at the worst scenario?


I don't think it makes much sense to consider the "worst" scenario. The best scenario probably involves you finding a new advisor.


  Is it normal (of course it's not!) that somebody that has nothing to do with a paper question the contribution of a paper that is not published yet even?


No, it is not normal for someone with no involvement in a paper to concern themselves with authorship issues for that paper, at any stage.



I don't see any reason to bother convincing your advisor. You cannot reason with someone to change a position that is not based on reason in the first place.

Given the pattern of issues you have had in the past (for example: Is this violation of academic integrity if I ask a question on Github public repository and post it as an issue? How to deal with an adviser that wants to force you to get his desired results?), your next steps should involve getting out of this situation in whatever way you can. This advisor is an advisor in name only, I cannot see a positive outcome if you stay with them.