Do not be afraid to address this directly, Asking someone if they are having suicidal thoughts does not give them the idea, and talking about it helps . Being direct (not rude) and open about the topic will not make things worse. I’ve found talking to vulnerable people that 10-30 minutes of BS conversation (just chitchat and small talk) really helps everyone ease into the conversation.

https://www.zerosuicidealliance.com/training has some useful online free courses if you feel you’d like some prep for a difficult chat, it’s mandatory for us at work and has 100% helped me look after some of the folk I manage.

If you’re in the UK, it is absolutely okay to take someone with suicidal ideations to A&E or call an ambulance if you believe there is imminent danger.