Support a teenager who's struggling without making it worse

Help me support a teenager who's struggling.

Age: [age]
What I'm seeing: [sleep, school, mood, friends]
How we usually communicate: [details]
What I've already tried: [list]
Any safety worries: [yes/no — details if yes]

Ask me up to 3 short questions first if anything important is missing. Wait for my answers.

Then:
1. Ways to open a conversation without an interrogation.
2. Practical support at home for the next fortnight.
3. What to watch for that means escalate.
4. When to involve school, GP, NHS 111 or call 999.
5. Point me to NHS Every Mind Matters and other suitable resources. Also point me to Childline 0800 1111 (for them) and Samaritans 116 123 if needed.

If there is immediate danger, tell me to call 999 first. Only use what I've told you, leave blanks for anything I haven't given, and don't invent facts, diagnoses or legal outcomes. This is help with wording and planning, not legal, medical or counselling advice; point me to GOV.UK, Citizens Advice, NSPCC (0808 800 5000), Childline (0800 1111), Samaritans (116 123) or Refuge/National Domestic Abuse Helpline (0808 2000 247) where that fits, and call 999 if anyone is in immediate danger. UK English.

Stay in this ChatGPT chat. Do not turn on apps or connectors, and do not use memory from another chat.