if you get ERD, you will stay put at wherever you go until the servicemember PCSs. they will only pay to move you to the new duty station from where you ERD'd to. This may be HOR, or if he already has orders in hand, to the next Duty station, although that in itself raises issues..in some cases, you may not actually be allowed to access the facilities until he is actually checked in to the new command...so no housing or Priority access to medical care.
ERD/ARD is typically only granted for those SM stationed OCONUS.
the family may NOT return to the Overseas duty station at the end of the deployment, they lose all SOFA sponsorship and are no longer eligible for housing or COLA.