It is wrong to kill your neighbor, especially if your neighbor is against the idea. No healthy person wants to be killed, and in that sense, it is correct to state that killing is objectively and morally wrong.
That is the most ridiculous attempt at an argument I've ever had. An argument is really just a relaxed form of proof so think about what you are saying in a precise manner:
Assumptions: No healthy person wants to be killed
Conclusions: Killing is wrong.
This conclusion is invalid. You need the following additional assumptions:
1) Only things that are "healthy people" can be killed. This is obviously false because a sick antelope can be killed.
2) Moral actions are approved by everyone. This is also false, obviously.
Finally, the one assumption you did make is false. People frequently want to die. And when they do it, it's called suicide...