Yechi Hamelech Hamoshiach!
Just like the word “Modesty” by the way it is practiced in judaism, does not mean the same thing as what the "world's" perspective on “Modesty” means - so too, when you say “Alive in a body” in judaism, it does not mean the same thing as what you may have thought based on what you see in the world.
In the world - if you don’t see somone (like when Moses went up on Mount Sinai) he is dead - or if you buried someone and at the time he seemed 'dead' - then you would assume he is dead - however in judaism that is not the case. starting with Yaakov avinu - who smiled when Eisav’s head rolled off -and this smile happens after Yaakov was officially dead - we know from the Torah "yaakov avinu lo met" he is alive - and obviously his soul is alive - but we are talking about his body.
To further understand this, we need to know what do tzadikim do all the time? The answer is; good deeds - after many years of getting their body worked up on doing good deeds their body becomes a true vessel "merkavah" of G-dlyness - and because G-dlyness is true, and they connected themselves to g-d which is truth and everlasting - their bodies cannot expire - because truth is forever - thus they live forever - moshe, yaakov, king david, pinchas, and many others simply live for eternity - body and soul together - now- this that we don’t see this is because g-d does not let/want us too, why? g-d needs to "Reward the good and punish the bad" and to give people a chance - i.e. free choice - g-d needs to "maintain" a situation that is fairly balanced.
