Text is a terrible place for tone. If it’s serious, call.

Written messages arrive without a face or a voice, so the reader supplies the tone themselves, and a tired or worried reader supplies a worse one than you intended. Nothing you can add fixes this reliably. Jokes read as coldness, brevity reads as anger, and the reply comes back to the version they imagined rather than the one you sent.

If something is serious, call, or say it in person. Save messages for facts and logistics. When a thread is already getting tense, the fastest thing you can send is a message asking if they are free to talk.