You could keep it supportive and light. Here are a few options:
1. "I’m glad to hear you’re starting to feel better! If you want to talk or hang out, I’m here for you."
2. "Thanks! I’m just looking out for you. Let me know if you want to chat or do something fun!"
3. "I'm really happy to hear that! Remember, I’m here whenever you need to talk."
4. "No problem! Just take it one day at a time. Want to catch up soon?"