Hi Sakura and
to purrs
I've only just read this thread, which is obviously generating a lot of debate.
I'll be honest, I don't know a thing about breeding cats
Without going inot any moral or ethical issues (which have already been debated here) the only advice I can offer is to think very carefully before making a decision. It might be worth getting both cats (your girl and mum's boy) checked over by your vet, and ask about the potential implications for her health if she is bred from, given her status as a carrier of cat flu.
Personally, were I in the same situation, I would suggest that you try fostering pregnant cats first, to get some hands-on experience of pregnant and nursing cats, and very young kittens, before I took to breeding myself. All the advice and info in the world won't replace practical experience. I'm sure your current girl is wonderful, and that she would likely have lovely babies, but given her prior health problems, it might be too much for her. Maybe you could get her neutered, foster a few pregnant cats to get experience, and then decide about whether to become a breeder or not.
I can understand you wanting to have kittens around, or maybe you feel you would like to have kittens with temperaments like your current girl, but bear in mind that "not now, not with this particular cat" doesn't have to mean never. Talk to your mum about what its like to be a breeder, and get some experience through fostering (at least this way you'll get the added support of the CP - you won't get that if you go ahead on your own for the first time), then decide what you want to do in the longer term.
I personally wouldn't breed cats, but thats because I don't feel capable or experienced enough, I would be too worried about the heath and potential medical problems, and because I would rather get rescue cats. However, I think it is good that you are seeking advice before you do anything, and I hope that whatever you decide to do, you will at least try to get some experience, advice and support from CP through fostering pregnant cats before you decide one way or another, though I would suggest that breeding from your current girl might not be the best for her health (remember that even if you give her the best possible care, things can still go wrong, and she's already had quite a difficult start in life, so might no cope as well as other cats).
Good luck, Sakura, whatever you do, and good for you fo volunteering with CP, and for doing your homework before making a decision.