Well, I think the best way is ... no right of living in HK for those only have 1 parents is hk person. This can reduce many many mainlanders to give birth in hk and can reserve places for hk mami & for overseas people/mainlanders like your friend for special needs.
In fact, 政府及醫療政度 is already so full, it can't even cope with the needs of hk person. How can it also cope with, even 1% of 13billion mainlanders !!!
You can't blame us because imagine if you are one of the hk mami who can't receive the service (private or public hospitals) which they deserve (don't forget they pay tax !!!), will you still be so claim?