"This is another trick of shrinks. They never let you stop in midthought. If you open your mouth, they want to know exactly what you had the intention of saying." ~ Ned Vizzini, It's kind of a funny story
If you have a friend going through depression and truly want to be a friend, you can refer them to a number of resources.
First, see what your college has available. Most colleges have a number of on-campus resources, such as therapists and counseling options. If they do not, there is likely someone you can get in touch with that will have a list of external therapists you can direct your friend to. Remember that it may be helpful to offer to go to therapy with your friend.
Most colleges will also have offices such as ADSR (Access, Disability Service and Resources), which help individuals handle necessary accommodations for coursework, which may occur if a friend has to go to the hospital for a period of time for treatment. This can be a stressful process that you may be able to help your friend navigate.
However, college does have breaks and does not last forever, so it is important to be acquainted with a number of national resources that are available at all times.