Is one sinful for failing to meet the condition of returning to and working in their home country after being sent abroad for study, given the deteriorating security conditions and widespread chaos there?

There is no sin upon you for what you have done, and you are not obligated to return to your country, as long as you do not feel safe there, especially if salaries are delayed while you are in need of them. This is because safety for oneself, one's family, and one's wealth is a fundamental condition for a place to be suitable for residence and dwelling. The absence of safety permits Islamic concessions (rukhsas). If some acts of worship are waived due to the loss of safety, then the contracts and conditions of people are likewise affected.