Related Rule
United States of America
Practice Relating to Rule 138. The Elderly, Disabled and Infirm
The US Field Manual (1956) provides: “The Parties to the conflict shall endeavour to conclude local agreements for the removal from besieged or encircled areas of … aged persons”. 
United States, Field Manual 27-10, The Law of Land Warfare, US Department of the Army, 18 July 1956, as modified by Change No. 1, 15 July 1976, § 256; see also § 44.
The US Air Force Pamphlet (1976) provides: “Removal of … aged persons … from besieged or encircled areas is encouraged.” 
United States, Air Force Pamphlet 110-31, International Law – The Conduct of Armed Conflict and Air Operations, US Department of the Air Force, 1976, § 14-3.
The US Field Manual (1956) provides:
Special facilities shall be afforded for the care to be given to the disabled [POWS], in particular to the blind, and for their rehabilitation, pending repatriation …
The Parties to the conflict shall endeavour to conclude local agreements for the removal from besieged or encircled areas, of … [the] infirm …
Civilian hospitals organized to give care to … the infirm … may in no circumstances be the object of attack, but shall be respected and protected by the Parties to the conflict …
Convoys of vehicles or hospital trains on land or specially provided vessels on sea, conveying … the infirm …shall be respected and protected in the same manner as the hospitals provided for in Article 18. 
United States, Field Manual 27-10, The Law of Land Warfare, US Department of the Army, 18 July 1956, as modified by Change No. 1, 15 July 1976, §§ 107, 256, 257 and 260; see also § 44.
The US Air Force Pamphlet (1976) provides that the “infirm … must be the object of particular protection and respect”. 
United States, Air Force Pamphlet 110-31, International Law – The Conduct of Armed Conflict and Air Operations, US Department of the Air Force, 1976, § 14-3.