Not all lawyers are created equal. I hired one to help me with my employment issues and it has helped a lot. For one thing, it helped "persuade" my HR department to back down from an aggressive (and legally erroneous) position regarding my work status.

Some things to look for: highly reputable law firm, reasonably experienced (mine is a partner in her 40s), law firm and individual lawyer specialization in disability cases (ideally with a decent level of awareness around brain injuries and PCS), and/or issues related to your particular employment. In my view, it's better to pay a bit more for somebody really good than to scrimp and get some junior associate who is less likely to provide good advice and/or get the job done right the first time.

Once you have found a good lawyer, it helps to be very clear and specific regarding your concerns about work and your symptoms/limitations. Identifying key concerns and communicating them by email can be helpful. Make a list of questions to ask prior to speaking with them.