it isn't easy. But I can assure you that the actual discomfort of confronting a loved one is much LESS than the anxiety that might stop you from it.
Most of the time the person is glad that someone actually gives a damn about them. The road ahead for them isn't easy at all and has ups and downs. But that initial event of letting them know you care enough to tell them what they don't want to hear is very often the single catalyst they need to turn their life around.
It doesn't always end in a success story, but you do owe it to them AND yourself to do it.