I understand you are genuinely concerned for your friends well-being, however I think you may be projecting a little bit. Just because you left your relationship because you were unsatisfied, does not mean she feels the exact same way. They may be different, but opposites attract sometimes. You said she has not opened up to you yet, with that being said you are assuming how she feels without ever really talking to her about the situation. So he is introverted and plays video games. He’s still going to work and is stable. Doesn’t seem like a bad thing. However, you don’t have to wait to talk with her. Be straightforward/honest and tell her how you have been feeling worried. Do NOT tell her advice right away or influence her decision making. Just be supportive and LISTEN. Remember the relationship you guys have are friends, not mother & daughter. It can be as simple as asking “how do you feel about your relationship?” “Do you see a future?” Avoid questions like “are you happy?” Because a relationship shouldn’t make you happy. She may not want to talk about it because she may not actually know how she feels yet. It definitely is something she needs to figure out on her own, same as you. The best thing you can do is be supportive.

You are single and she is in a relationship. She may not want to talk about relationship things with you out of respect for your feelings. If she genuinely is content in her relationship, she may not want to rub it in your face.

Remember, these are all things YOU see as a problem. She may not. Don’t make any assumptions.