Penalties in the US for simply having marijuana depend on how much you have, and where in the country you are.
For example, in California, you cannot be arrested for possessing 25 grams of marijuana (and will only be fined $100), but 50 grams is up to 6 months in jail and a $500 fine.
In Oregon, where I'm from, 25 grams is worth a fine of $500 to $1000 and no jail time, but 50 grams could earn you 10 years in prison and up to a $100,000 fine.
In Washington, where I am now, 25 grams is worth one to ninty days in jail, and a $250 to $500 fine, while 50 grams is up to 5 years in prison and $10,000.
In Arizona, any amount, even a very small amount, will get you six months to a year and a half in jail, and a fine from $750 to $150,000, but the sentence can be suspended in exchange for probation and drug treatment if you don't have a prior record of drug convictions.
The M to C+ sentences are fairly extreme, given a small amount for personal use, but the L and L+ are normal to lax by current standards. Of course, since L currently lists marijuana as legal in the game, that makes sense, but it's still not likely to cause a scandal.
One problem with using the college student example is that those who already are holding Conservative views on the drugs issue aren't likely to look kindly on the college student -- they'll easily see him or her as having destroyed their own life, rather than blaming the government. So more extreme may be necessary here.
Looking to Capital Fish's suggestions, if he was convicted of growing or selling, that would dramatically increase the weight on him, and the sentencing could easily get out of proportion, even for a small amount. If he was struggling with cancer himself, and had been growing marijuana for personal use for pain and nausea relief, that would also make the effective amounts he was convicted of increase radically. For example, if he had five plants in his apartment, dormroom, or parents' basement, he could potentially be charged treated as a dealer in possession of over five hundred grams of marijuana and sentenced to five or ten years in prison.