I assume (/hope) SV means the doctor has been contibuting part of his salary and paying VAT etc on his purchases to help fund the UK's armed forces.
I understand the argument that it should be UK citizens first but if there is spare capacity (which I understand there has been on some flights) the surely those with the right of abode should be able to take the spaces.
The question of close family members with no right of abode is a humanitarian question that also needs addressing.
What duty of care the UK owes the ordinary Sudanese depends on how strongly one feels Sudan is yet another state Britain granted independence to under a democratic regime without providing the support to help it thrive. (I am assuming NBCD State 1 Condition Zulu Alpha)