There's VPI Pet Insurance; which our pets were on until my parents dropped the account(still muttering in anger about that). There's two types of payment plans, and pet insurance is really worth the monthly(or yearly - whichever option is chosen) fees, for the help it gives you when it gets to be vet-time.
Don't regret posting! Please! You're trying to help a kitten, and that's what matters. You know... people make mistakes, and your mistake was all in good heart. To try and help a poor kitten, rather than sitting by and twiddling your thumbs, your heart was totally in the right place.
The downside is, if the kitten dies, that's on your friend's conscious, and shouldn't be on yours.
The upside is there's hope. There's always hope. But buck-up, which I know you can do because you had enough heart to try and help the kitten, buck-up, and tell them what you did, and as a friend, you're concerned for their kitten's sake and that's all that's been on your mind and you never meant to offend. If she's a true friend, she'll understand. If she isn't......
And of course, make sure she knows there's options. Humane societies..no-kill shelters.. Maybe if she knows there's options besides feeling "cursed" with this kitten's "disease", maybe she herself will buck-up and make the right decisions.