Odds are if the manager really liked him, the manager would have liked to give him a raise.
However, sometimes available finances simply do not warrant a raise. Sometimes higher management who does not know an employee says "why should we pay him more, we can just find another Joe to do the same job", without knowing the measure of the man.
A lack of raises in minimum-wage work is the norm. I know people who've worked in franchises for years who've barely been given raises (which are normally cancelled out by a minimum-wage increase a few months later anyway).
Why don't these companies give raises? The same reason Wal-Mart fights viciously to stop unionization; because higher-pay means higher-prices which for bottom-of-the-barrel pricing means less sales. I can buy a burger at McDonalds for a dollar; I have to shop like a pro to find the deals to get burger buns and burgers, cheese slices, pickles, ketchup/relish/etc at a comparable price to make an identical burger. Likely I'll end up spending at least $2 to make my own burger.
McDonalds is making profit off of a food item that costs less than $1. Looking at the economics of it, it's ridiculous. How many burgers in my lifetime would I have to make to equalize the cost of using electricity/gas to heat my stove top to fry a burger, and buying the frying pan in the first place, and the bun, burger, cheese, condiments.
Not giving a raise helps keep these people in a job, it's sad that it has to be this way (for more reasons than one), but thats what this world is. Although to look in the back of most McDonalds if you found one competent worker like Mr. Smith you could fire half of your day-staff. I've seen 3 good workers turn out orders faster than when every station is full and there's 20 workers in a store, because when there's a lot of them they're inevitably students and the managers are like 19 and endlessly chatter.
However, sometimes available finances simply do not warrant a raise. Sometimes higher management who does not know an employee says "why should we pay him more, we can just find another Joe to do the same job", without knowing the measure of the man.