Well first off I would ask it, but I would wait until you're both in a position to talk and be candid about the situation. If she's in the house or around someone she doesn't want to hear, she will not be responsive in the way you want. Similarly if you text out of the blue "hey did you ever take the pills?" you're less likely to get an answer. So wait until youre in a conversation where you're being open. One good way to make her feel comfortable might be to open up to her about a struggle of your own. This will make her feel like she's not alone in struggling in general, but also that you trust her. She is more likely to give this trust back. Then, after discussing your own business, you might want to ask her how she's doing. Follow up with "i recall the doctor saying you might benefit from antidepressants, did you ever take his advice?"

Its important to say "take his advice" rather than "take the pills" because it's a less direct way of saying it and less likely to cause anxiety if she doesn't want to mention she's taking the drugs.

If she says yes, tell her that's probably the right thing to do, and there's no reason to feel ashamed about it. Doctors are there to help, and everyone needs a little help every now and then.

If she says no, ask her if she's getting help in other ways. If you feel her way of coping is enough, then congratulate her on taking control of her struggles. If you don't, mention above.

Its important that people know that needing mental help is nothing to feel ashamed about. Some people think they can cope without it, but don't see how beneficial they can be. If we get the flu, we take medicine to make us feel better, if we break our arm we get a cast or bandage. When it comes to our mental health, we need aid there too. Its not always permanent, but sometimes we just need a little aid. As long as you're there as a friend to help her though it can make her journey to healing a world of difference. And it's evident you care from asking. So good job on that