Three words: Provent-a-Mite. A wild snake is almost certain to have them.
And Gale's right - check on the legality. But my thoughts, to very simply answer your question, is that if he wants a bullsnake so badly, get one from a breeder and let the wild one go.
Wild snakes often just don't do well in captivity. Sure, wild caught BPs are imported all the time, but they are notoriously hard to feed and keep and often loaded with parasites - some of which don't neatly manifest in a month or two long quarantine. 6 months is the shortest QT I would recommend for a wild snake - and this is STRICT QT: seperate rooms, changing clothes, washing thoroughly without fail, seperate feeding days, the works. Is that overkill? Maybe, but it's safer. IMO, it's just not fair to keep a wild-caught native species in captivity. Not when you can pick up and nice, healthy, captive bred individual for not much money.
Your boyfriend will understand once he goes through the fun of a rept expo or talking to a good breeder and is able to pick out his own snake that way. ... Or at least, he should.
These are just my thoughts.....
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