Is moksha mithyaa?

A friend of mine came up with a question: Is liberation an illusion? I'll interpret that as Is moksha mithyaa? since mithyaa is inappropriately translated by many as illusion eg. from brahma sathya jaganmithyaa. So actually the question, in English, may be read as: is liberation unreal?

Here's how the discussion went:

me: do you mean that whether our search for liberation is unreal or liberation itself is unreal? For former, yes, for latter, no!
he: what if one quits everything in search of liberation and finds out 30 yrs hence that it wasn't a good decision?
me: On reaching liberation... as in, it was a waste of time and wasn't worth it? Or do you mean that one doesn't find anything even after a painstakingly long time/era?
he: not like that... say, there's nothing like liberation!
me: that means that either there is something like that and that person didn't reach it being unqualified or less of efforts, or else, having reached it (something that he calls liberation) felt that his earlier way of life was better!

Say, renouncing state X, one goes to state Y (whatever this state Y is). If he feels state X was better after reaching Y, that means even today, before renouncing X, he fears that his worries may be true. In which case, there isn't enough faith in Y. Lets say, hypothetically, that X is thought of as better on reaching Y, then that person thinks that there's no liberation (in the Y state) and leaving only two possible things:
i) X was better, he was blissful there itself. That is the real goal which he'd already reached. Probably, the chaarvaak way.
ii) There is nothing, neither liberation, nor anything else. As in, no state, *shunya*. Perhaps, this is what is the Buddhist way is. In which case, his renouncing X was right and then, he needs to renounce Y too!

And in either case, it would be the belief about the path/destination. So there is no finding out the right destination without treading the path.

This discussion continued afterwards and it went thus...

me: another thing I want to say is that after reaching Y, the person (bringing out such doubts) has the same tools at his disposal to argue (mind/intellect, etc) that he had on the onset at X.
he: No, these tools will disappear with the negation of each.
me: in which case, as per vedaanta, he's on the right path, leaving him no reason to doubt the path.
he: with the faith/belief that we talk of, a realised (liberated) person can make the claims about the right path and people will follow that. But how does one explain his belief to others if he's a student, and convince others that he's doing the right thing?
me: who does he have to prove? To others, right? This other person will say "you're wrong". Thats his *belief* in *his* right path. He can't prove it either. So our sanyaasi is as right or wrong as the other and we have to make our own choice with the belief. Thats why AdI ShankarA talks of qualifications of a sanyaasi for jnaana yoga. For others, he does suggest karma/bhakti yoga for purification. The process is quite logical even to the existing set of tools we have for deduction.