Is this discrimination?

This is a situation that involves my mom who is 54 year old Filipino and works for a manufacturing company.
When the whole department works overtime except for her, is that considered a discrimination? I work for the same company as my mom but I am at the sales department. So when I found out about the situation I emailed her supervisor to see if he can explain to me if my mom has done anything for her not to be eligible to work extra hours or if there is anything that she cannot do that the rest can. But, I have received no response from him. Is there anything else I can do to help my mom as she is very upset about the whole situation? I'm afraid that they might retaliate on her if I go to out HR department and file a grievance. Any help would be greatly appreciated!!! Thank you in advance.

First things first: let your mom speak for herself, especially in the workforce. While your email was no doubt motivated by the best of intentions, you're crossing both legal and professional lines by approaching her supervisor on her behalf. That manager who failed to respond was doing so in compliance not only with likely company policy, but federal employment laws as well.

That's not to say you can't help here. Check your company policy; hopefully there's an employee handbook or other similar policy in writing at your particular job. Are they complying with their own procedure as far as amount of overtime, when assigned, to whom assigned, etc? What are your state's particular employment laws concerning overtime? Is the employer complying with those as well?

Personally, I'm noting 3 characteristics that jump out from your original posting, i.e. gender, age and nationality. (Understand this is only my opinion here and by no means, legal advice. I'm merely noting a coincidence.) You'd need to do some careful research (that can be documented) on how hours are assigned to all of the employees. Is there a glaring difference? Is a certain population being omitted? There are federal discrimination laws against at least the 3 characteristics noted above; your mother (not you) may have grounds to pursue. Best bet is to check with your local labor board after you've investigated your company's policy, then consult with a good employment attorney in your area. Jumping recklessly into a grievance complaint "unarmed" could conceivably cost your mother more than she knows. Get your mother (again, not you) good legal help there if the signs are pointing towards possible employer discrimination. Personally, I think you can best help by 'doing mom's/your homework' first and let a professional interpret the results.

Hope this helps. Good luck to both of you.