Yo,
As I said in your email, if I see the damage I can offer suggestions on how to fix it. Your brother seems to be on the right track-drill out the bolt and re tap it. However, if you just drill out the old hole bigger and retap the actual metal, you will end up with a bigger bolt size and it will be impossible to find a bolt the right size and shape-those drain pan bolts are usually pretty unique. My first suggestion is, if you can afford it, go with your first choice and buy a new oil pan. And yes, 91-94 CBR F2 parts are all exchangeable! Great for us huh? A lot of parts on my bike are off other bikes. Anyways my second suggestion is to, like I also said in the email, get a re-thread kit, which comes with the right size drill bit, and insert new threads into the hole. You can get these for around $20 from any local hardware store (not home depot lol). Just make sure to get the right size.