It's important to just be there for them in a non-judgmental way.
Try to engage them in activities that will benefit them mentally and physically, including exercise (going for walks or runs, assuming you're living together). Don't force them to talk about their feelings but do be ready to talk to them when they are.
Validate their emotions and express empathy, because we're all feeling anxiety during this time and they're not alone.
Dr. Ashwin Vasan