Appropriate clinical management means a treatment regime designed to cure, control or lessen the severity of a condition following its clinical onset. This may involve active intervention in the disease process by surgery, drug treatment, physiotherapy, chemotherapy etc. It may also be a more passive approach such as rest or the avoidance of certain foods.
The question of whether or not any particular clinical management of a condition is appropriate is largely a medical matter as what is appropriate in one case may not be appropriate in another case. Because of advances in medicine, appropriate clinical management in earlier decades may well have been quite different. For that reason, current treatment practices should not be used to gauge the appropriateness of treatment given in the past (even the recent past). Therefore you should seek medical advice as to whether a treatment regime can be considered appropriate clinical management of the veteran's condition.
An inability to obtain appropriate clinical management may have occurred because the veteran was in a combat situation, posted to an area with limited medical facilities, or because the condition was misdiagnosed. An inability to obtain appropriate clinical management for an illness or injury may also arise when the presence of another condition prevents a particular treatment being carried out eg a partial gastrectomy may not be possible because the veteran's advanced emphysema precludes him having a general anaesthetic.
Refusal of an offer of appropriate treatment does not constitute an inability to obtain appropriate clinical management.