If it's all you can afford, it's understandable. Personally I think if he is at the start of year 10 he will be able to catch up, and if the school could provide him with some work either on paper or online that would be even better. If there are timed assessments during this time there must be mechanisms for kids who are off ill, or on Hajj, or who join the school later in the year. After all it is in the school's interests to accommodate these pupils and not deny them access to assessments.
However - it isn't the best approach. Education isn't just about the factual content of lessons, but also emotional bonding, and kids miss more than the two weeks by not being there.
Is there someone on the satff you can talk this through with? economic needs are an important reason but for the lad's best future you need to be working with the school.