To me it just wouldn't make any sense if the Lord Jesus meant this:
"This Generation might or might not pass away till all be fulfilled."
Would it to you?
The bottom line is that something is wrong. For the literal TRUTH to say "Generation"... is false! It makes Jesus into a liar.
Family is congruent with the scriptures. I do believe that this matter was adjusted with selfish intention. We must use multiple manuscripts and all fragments available when attempting to glean the true intent of God through scripture.
I know this happens in prophecy because there is much pride in prophetic interpretation. Daniel and Joseph are epic for prophecy... but they simply relied on God... period. We are in the midst off events that are giving full light to Scriptural intent and the western Eschatology crew is too proud to acknowledge it. This is the kind of thinking that blinded people to Christ's first coming! It's no shock something of this magnitude is possible, in reference to Scriptural tampering.
I will simply say this... I believe there is another famous place like this in prophetic scripture where the word number should be multitude.
So I see "Family" in context of the Jewish nation as biblically congruent and accurate.
This holds much water.
Consider Mt. 12:46-50 in relation to what you are suggesting. It starts to rapidly build a contextual and cross referenced pace.
Cross Ref of Mt. 12:49 that seems to support this