Wife arrested on a 15 years old warrant (failure to appear) What's the worst/best case scenario?

Contrary to what some of these people think this is a very serious issue. Did she ever face the original charges? Were the original charges dismissed or cleared? Otherwise there is another matter from that end as well. Here is the problem though, and that is even if the original case is over, and that is it depends on the Judge she originally faced and is going before now(if it isn't the same one since 15 years is a long time). Different Judges have different takes on failure to appear. Was she found guilty on the original charges basically because she didn't appear? If not what will the Judge you face think of her. I mean we really don't know, but some Judges will throw the book at someone for failure to appear and "hiding" for 15 years. She KNEW she had to appear is my guess. That doesn't go away.

Get a lawyer, yesterday. Don't try to figure this out by yourself - people who self-defend or depend on free advice find themselves basically ******.

This is a serious issue though - not just failure to appear but because its a drug offense - she has done drugs and committed crimes in the past, allegedly at least. Running away from that just compounds the problem. Don't just hope it'll go away - hire a good lawyer now and tell them the entirety of your story - warts and all - to see what can be done.

She'll probably get a few Years of Probation ( & maybe a Fine ). But that's about IT. :)

Probably charges dismissed with payment of original fines

only an attorney who is familiar with similar cases in your area knows what the likely outcome may be. maybe you'd best hire one.