Not sure what to do

We've been ttc since for awhile and haven't told anyone since my doctor said we may have some issues. I just found out my sister has been trying to get her boyfriend to start ttc because she doesn't want me to be pregnant first and she thinks since I got married first she needs to have a baby to beat me. I didn't think it was a competition I'm just living life and she doesn't know we are ttc. Her bf confided in me so I just didn't react and said she shouldn't feel that way and I lied and said we aren't trying. He seemed really bothered about her reasons behind it and how pushy she's become and now I just don't know what to do I feel like her whole train of thought is just so messed up...