Whoever performs Hajj returns like the day his mother gave birth to him. As for someone who died and his family performed Hajj on his behalf, are all his sins erased? No.

This means something else, it means someone who did not perform Hajj.

Or he performed Hajj and then died after that.

And they performed Hajj on our behalf, no, not all his sins are erased.

Rather, this means there is a great reward, the reward of Hajj is a great reward, but the one who truly returns like the day his mother gave birth to him is the one who performed Hajj.

By himself, for himself, yes.