I would go for a simple answer:
Your friend should have a look at a hand full tutorials on both languages.
The one he feels most comfortable with and which he picks up more quickly should be the language of his choice.
Languages are made for people to solve problems. If he could pick up one language faster than the other he is faster in solving his problem.
The point in time, when hard benchmark numbers count is far in his future.
Every popular language is for most of the jobs "good enough". Many disadvantages could be compensated otherwise.
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