What is the statue of limitation for a federal drug crime in Texas when an indictment has been established?

The statute of limitations is tolled (stopped) while the case is pending (after charges are filed and certainly after an indictment). The issue the person may have is a speedy trial issue. However, s/he likely waived his right to a speedy trial at the beginning of the case (which is usual - it allows preparation). Have him/her consult his/her lawyer about how much longer. If s/he is cooperating, that certainly could be the cause for delay and a good reason to delay a case. S/he wants as much credit as possible (if cooperating.)

As noted in the previous responses, the statute of limitations is not implicated by the facts of this case where the person evidently was timely indicted. The issue is whether or not there has been a speedy trial violation.
Speedy trial law in the federal system may appear to have easily defined time limits, but don't be misled by trying to apply those rules to the facts of your case unless you are also familiar with the many exceptions to those time limits. You need to have the preson's lawyer (or consult another more experienced attorney with federal criminal experience) review what has transpired to date in the case to see if there has been a proper assertion of the defendant's speedy trial rights and how much time has run on the speedy trial clock (excepting out all that time which has been properly excluded by the judges in the case, at the defense's request, etc.). Only then will you know whether it will be possible to get the charges dismissed for violation of speedy trial rights. This is definitely an area where someone needs an experienced, attorney with knowledge of the federal speedy trial law.