Colonel Jendon says: at the start of combat phase, you may assign 1 of your blue target lock tokens to a ship at range 1 if it does not have a blue target lock token.

scenario: Jendon assigns his target lock to Turr. Turr died before he can use the target lock.

Now, the question is what happens to that target lock? Does it go back to jendon, or is it gone?

second scenario: Jendon assigns target lock as before, but Jendon dies before Turr uses it.

Again, does turr keep the target lock until he uses it? Or is it immediately removed?

Once the target lock is passed it belongs to the ship that holds it for better or worse.

I think a good rule of thumb in general is to ask which interpretation works under the rules as written, and which would require you to invent rules that don't exist to make it work. You'd be surprised how often the only reason questions come up despite the fact that one half of the question is clearly supported in the rules and the other half is not, at all. Makes you wonder sometimes how it was a question at all.

So in this instance, there's nothing in the rules that states a target lock would be removed once granted, until it's spent. Jendon's ability states he passes it, but nothing in his ability gives any indication that the target lock works any differently than normal once he's handed it off. If there's nothing directly telling you to handle that target lock as special or remove it once Jendon goes out of play, there's no reason to think it's anything but a regular target lock at that point.

But yeah if Jendon is gone and they SPEND the target lock, they have no means of getting it back, because the stated exception to the rule requiring the target lock action (Jendon) is no longer in play.