Does my father owe an expiation for not leaving the Haram precincts, knowing that we were standing at the boundary itself? And can I perform the expiation on his behalf?

"Whoever is in Mecca and intends to perform Umrah (definition) must enter into ihram (definition) from outside the Haram (definition) boundary, not from within it. It is obligatory for him to go out to the nearest point beyond the Haram boundary (adna al-hill) in order to combine both the permissible (hill) and the sacred (haram) in his ritual. If he enters into ihram from within the Haram, a compensatory sacrifice (dam) becomes obligatory upon him. If he crosses the Haram boundary and enters into ihram from the permissible area (al-hill), there is nothing due upon him. However, if he stops at the Haram boundary and does not cross it, then a compensatory sacrifice (dam) is due upon him."