Student or Learner
He is a freak of music, science, history and computer.
He is a freak about music, science, history and computer.
Which sounds good to you? If either way isn't, could you reword it, please?
I agree. Calling someone 'a freak about music' suggests they have an obsession rather than just enthuisiam. 'Freak of' is just wrong in this context; you can have a 'freak of nature', but not much else; it's a very strong collocation.
'Crazy about' / 'mad about'...
More here: http://http://corpus.byu.edu/bnc/1 FREAK OF NATURE 8
2 FREAK OF FORTUNE 2
3 FREAK OF FATE 2
4 FREAK OF PHYSIOGNOMY 1
5 FREAK OF PHYSICS 1
6 FREAK OF HISTORY 1
7 FREAK OF BREEDING 1
8 FREAK OF BIRTH 1