
Any one serious about their breed really ought to join their breed club where they can learn all about their breed and to find out about the current state of it's health issues and what measures members are taking to address these.
To do otherwise is really like walking around blindfolded.
Details about health can be found here:
http://www.frenchbulldogclubofengland.org.uk/healthscheme.htm on the French Bulldog Club of England Website
http://www.frenchbulldogclubofengland.org.uk/I would also advise that your friend attends shows to see the what dogs are producing what,a and to get to know more owners and breeders before embarking on breeding.
The bitch seems to me to be quite young enough not to be considering a litter just yet, so time to do some research.
Past breed club yearbooks can be very informative, you will need at least 10 years back to get an idea what different lines are producing.