Clarification of a "Gift of Residue" clause

I’m trying to verify that the following ‘Gift of Residue’ clause ensures that in the event of either of the named beneficiaries dying before me and their having left no children surviving me, then their share of my Residuary Estate would not pass to their spouses but would instead transfer to the other named beneficiary and/or their ‘issues’?

“I give my Residuary Estate for such of my daughter DAUGHTER_NAME and my son SON_NAME as shall survive me and if more than one in equal shares and if either of them shall fail to obtain a vested interest leaving issue who survive me then such issue shall take by substitution such failed share and if there shall be more than one of such issue they shall take in equal shares per stirpes but so that no issue shall take whose parent is alive and so capable of taking.”

I would be very grateful if anyone could help.

Based on the wording of the clause, if one of the children died before you without leaving issue then the surviving child would take the whole and the spouse of the deceased child would not benefit.

Patrick Moroney