Is there any special tools that are required to repair my friends cars tie rod? She has a 1990 Lexus ls400, she has all the parts, but is unsure if she will be able to repair it. She does not want to be stuck with the car being parked or towed to a repair shop! This will be more additional expenses that she can NOT afford...

Would I be out of line to assume that you mean the outer tie rod end?
The outer is the one that is most likely to wear...
... so, no. No special tools are needed. Only the sized wrenches necessary.
Loosening the jam nut does take a fairly large wrench compared to most home DIYer's tool box. Hefty channel lock pliers can be used if used properly.
Getting the tie rod end loose from the steering knuckle will require a large hammer.

IMPORTANT NOTE:
Once the worn tie rod end has been replaced, you will need to have the alignment check and reset to minimize tire wear.

It's best to use a puller to unfasten the tie-rod end. Mark the threads with Whiteout, in order to install the new tie-rod end in the same position as the old one. Replace the cotter pin with a new one.