Is it obligatory for a person walking in the desert who has water to give it immediately to someone thirsty, while fearing thirst in the end?

"Al-Majmoo‘" mentions two possibilities regarding which of them should be given precedence. The preponderant view is to give precedence to the thirsty person immediately if they fear perishing, because the destruction of their life is certain, unlike that of the owner. If one is in a wilderness and despairs of finding water, and it is highly probable that they would perish if they were to give away what they have, then the closer view is that giving is not obligatory. Similarly, if the thirsty person immediately fears the loss of a limb or illness, and the owner eventually fears the loss of life, then giving is also not obligatory.