Is it possible to help them without being pushy or detrimental to their current state?
For myself I found that the Source Natural brand worked and the Walmart brand did nothing.
Speaking from my personal experience with my late wife, I know that it is hard to watch loved ones suffer. In the end the best option is usually to just be there and listen. Males tend to be Mr. Fix It and in general Females don't like that. Takes a while to learn. The book Men are From Mars and Women are from Venus goes into detail.
https://www.nccih.nih.gov/health/sadenosyllmethionine-same-i...
Then I think that depressed thinking often arises due to disharmony within the body, so that although the symptoms of depression are often found in someone's thinking, no cure can be found for depression in addressing the issues that seem to be at stake. Depression is not usually caused by any historical experiences no matter how terrible and is not caused by a "bad attitude".
Because depression has so many potential somatic causes, there can be no generally effective treatment for depression. Certain drugs are touted as achieving good results, using certain measures, but nobody takes those drugs and is thereby healed.
I believe that the best (or only!) things I can do for depressed friends are 1) to explain to them that depression is not their fault and 2) to support them by letting them be a part of my life.
"High fried food consumption impacts anxiety and depression due to lipid metabolism disturbance and neuroinflammation"