With all due respect, your post sounds as if you’re asking whether this particular stock is a good bet. It has previously performed below expected levels, but that might just be due to the recent recession. Will I get a good ROI if I invest in it now?
I don’t think you’re that callous, but I don’t think you’re asking the right question either. That question should be, “how can I help my stepson work toward his newly stated goal?” And the answer is “do anything you can.” It is always worth investing in a child, but what you invest doesn’t necessarily need to be money.
Get to know him. Find out why he wants to be an engineer. Help him see the difference between a good engineering candidate’s GPA and his own. Ask him what he thinks he can do to bring up his grades and be available to him to answer math questions whenever you can. If he wants a tutor, and you can afford it, hire one.
But keep your expectations for a turn-around reasonable. A gifted math student can perform well even at a low-achieving school, so this may not be his thing. If it turns out that he’s not cut out for engineering, help him research careers that may satisfy his interest in engineering without its demands.