Is Having Suicidal Thoughts a Sin That Takes You Out of Islam?

As-salamu alaykum. I'm asking for a friend who's been going through a really tough time. They're wondering if seriously thinking about ending their life would make them leave Islam. Like, does having these dark thoughts mean you're no longer a Muslim? It’s been heavy on their heart, and I want to help them understand what our deen says about this. Jazakum Allahu khayran for any guidance.