"I was helping him at work."
Translation:Pomagałam jemu w pracy.
As often - it is sometimes possible, but in very limited contexts... imagine this:
Jemu pomagałam w pracy, jej pomagałam w domu, a im pomagałam w ogrodku.
(Him - I was helping at work, her - I was helping in the house, and them - I was helping in the garden)
So I guess it's better to reject such answers, than to lead someone to an impression that this would be natural.