Brother according to the experts of hadith sciences …
A weak hadith is not a falsehood it never has been false … fabricated hadith have their own classification
An authentic hadith also does not mean it is truth, rather it means it is reliable based on a certain criterion.
Many sound weak hadith from different sources on the same topic collectively give each other weight and increase the topic to a trustworthy one.
For something to be deemed haram, fard, kufr, it requires authenticity (as far as I understand), otherwise weak hadith are enough to hold a trust on for matters pertaining to goodness, disliked things, etc , otherwise we will be rejectors of hadith. Even weak hadith have their purposes.
The Mahdi - is a not the prophecy of other nations. Rather Islam is unique in that it has two people, Mahdi (AS) and Isa (AS).
It makes sense for other nations to have similar prophecies because according to our hadith the Mahdi will affect all nations. And why cannot all the sources be from truth?
Even when it applies to Shi’a versions of Mahdi, there is no proof that Mahdi as a concept is isolated to Shi’a sources. Rather the reverse is happening. You are beginning to fall into the trap of the time that will come when people will begin to doubt the Mahdi.
People are already doing it. He will come when he is least expected according to other traditions. Take it easy … do your obligations in Islam and if he comes embrace him, if not then don’t worry about it, but do one thing for sure … learn about who and what he represents and how you will recognise him and Isa (AS).
Good points raised Psyah Bhai,
This fact should also be noted that all major religions of the world are waiting for some promised one to lead. Muslims are waiting for Mahdi, Hindu for Krishna and thinking about this Islam is the final religion and Quran is the final book and Allah I guess wont be sending a Mahdi for each faith. Allah likes unity not division.