Your friend is in a tough spot. Regardless of what her lawyer told her, she is still responsible for reporting to her probation meetings and fulfilling the other conditions imposed by the judge. It sounds as if she has absconded for several years and has avoided being arrested so far. She is potentially on the hook for up to the maximum amount of time in prison that the judge gave her when she was sentenced back in 1994. What happens is ultimately up to the judge whose court she was on probation in.
Your friend needs to contact a lawyer that practices in Denton County and discuss her options. Most attorneys do free consultations, so she should be able to get a local perspective about what is likely to happen if she turns herself in.
Disclaimer: This answer is provided as a public service and as a general response to a general question, it is not meant, and should not be relied upon as specific legal advice, nor does it create an attorney-client relationship.