I was asking for clarification. I understood it as Red Skull was immortal while guarding the Soul Stone. He hadn't aged in 70 years even though, unlike Steve Rogers, he wasn't frozen. Rogers obviously aged so I doubt he could be the guardian like this dude is claiming.
OK here we go....
Like the red skull stated in IW the soul stone is unique among the Infinity stones in that it has its own consciousness.
To take it to comic book levels the soul gem had its own world inside of souls.
Adam warlok lived in the soul gem until the events of the infinity gauntlet necessitated him to leave and battle thanos.
All of the souls dwell in the soul gem and age or time does not effect them.
We can see this when thanos snaps he sees gamora as a little girl. There was a deleted scene where Tony saw his daughter Morgan as a grown woman.
Based on this, what dude was saying is the soul stone was Steve's and could not be returned. since Steve is the master of the soul stone he can call upon any soul/occupant to assist him. This is also in keeping with what happened in the comics.