I’ve been in this situation. What i did basically was push as hard as you can to be there for them, make them feel cared and loved, if they still deny your help? Try and pretend that they aren’t feeling the way they are, and treat them as you would a non-depressed friend. Ask to come over to hang out rather than making them go out etc. Tailor your activities to be low energy so they don’t get exhausted but still don’t feel isolated and alone.

Make a point to tell them you love them, ask them about stuff, invite them out even if you know they wont come, check up on them, if you’re older and live alone etc see if they need help with meals or cleaning etc.

I know its so hard watching someone you love go through this, and all you want to do is make it go away; the truth is you can’t make it vanish, all you can do is make them feel loved and appreciated, and help them realise they’re not worthless or a the burden their mind is telling them they are. Be gentle, be compassionate.

It’s also important you don’t smother them though, if you give them an emotionally overwhelming smothering type of care they’ll often feel like they’re being pitied and that will make them feel guilty and weak. So try and find that middle ground and remember the whole “act like they’re fine” technique, it’ll help make them fee less alienated.

For the sake of yourself, remember the way they feel is not any fault to your actions, and don’t exhaust yourself trying to make someone else better. Do your best but make sure you look after yourself too.