Living longer as a form of happiness only applies to a small minority of 6 Billion population we r talking here.

Now, sustaining one human living modern lifestyle - take US for example would need as much as few thousands of dollars to continue for that lifestyle in 1 month. This money in turn is calculated into amount of resources used: Petroleum, Tree, Water, Oxygen, Clothes, Space, Soil, food and yada yada.

So, making humans live longer will definitely bring trouble into the next level as a whole human population are taken into account.

Thus, summary: Living longer doesn't solve anything in the world.

This is not even the road to immortality, what we perceive Immortality is that he is no longer subject to many human basic needs. And by any means, he no longer have basic emotions too. So, Immortal is someone who will never die and will never succumb to mortal wounds. So the term mortal =/= immortal because of the word 'im' is attached to the word "mortal".

So, this discovery is pure bullcrap, making someone younger is only an anti-ageing process. So, meaning that making someone look younger or his insides are younger and healthier.
No matter what, he will still succumb to mortal wounds.