A man whose 15-year-old daughter died six years ago after taking the prescription drug Prepulsid was celebrating a minor victory Monday after an Ontario judge gave her stamp of approval to a Canadian class action lawsuit against the drug’s maker, Johnson and Johnson Corp.

Terence Young, who served as a Conservative member of the Ontario government from 1995 to 1999, said he was experiencing “joy mixed with frustration” in the wake of the judge’s decision.