Answer:
6
Explanation:
Richard gets 7 more sweets than Gavin which would probably make Richard have the most so in total he should have around 8 whilst Gavin has 1 so right now we have 4:1:?. Basing off the fact that Richard would have the most sweets Henry would have to have 6 sweets to be able to divide half of it for 3. 4:1:3