the local pet shop where i live has a tiger morph Reticulated Python just like the one your cousin has, there beautifull snakes and I am fasinated by them however I am a long way if ever from being able to care for one. The one at out local pet shop is 5 years old and 22 feet long this snake is huge.
I have been reading alot about reticulated and burmese pythons as i find them intresting and from what i have read they grow Fast.
Not to mention every year there are horible incidents where these large snakes turn on there owners, and even some experinced owners have had close calls, I Just watched a video on animal planet about a retic that attacked his owner and killed him, if not for a maintence person he would have stayed dead. This incident was the onwers fault he entered the encloser alone with a large snake to change a lightbulb when he knew he should have had 3 other peoples help.
If i where you I would sugesst you do some reasearch on these snakes to show your cousin how dangerous they can be and try to convince her that what is best for her and the animal is to find some one with experince that is willing to care for it.
to give you an idea of how powerfull these snakes are that perticuler retic coiled around the man and he was dead with in a minute. These snakes are wonderfull creatures but should be respected, and only some one with experince should attempt to handle these snakes.