Remember when it comes to major life decisions no one gets to decide but only you. So to this problem, friend can’t do anything to convince his parents but he can always ask himself if taking science or being a doctor is something that he really wants in life. Not having outstanding grades in science doesn’t mean that he can’t be a doctor. Anyway, he can always decide for himself. If it is English, geography or history that he thinks can give him a better career in the future, there are numbers of career options also for him. He can be a teacher, a writer, landscape architect, etc.