The IDF's former Chief of Staff Moshe Levy is in unconscious in serious condition after suffering a second stroke.
Levy, 72, was born to Iraqi immigrants and was Israel's first IDF Chief of Staff to have served only in the IDF. Levy is too young to have served in any of the pre-State militias. Levy's nickname, apparently picked up early on in the IDF, is Moshe and a Half (Moshe v'hetzi) because he is tall.
Saying a brief payer (a chapter of Psalms is the norm) for his recovery and/or doing a good deed in his name for his recovery (for example, giving charity or doing some volunteer work) is the traditional Jewish response to situations like this. In other words, take a moment an do something good with the hope that God will repay that good with healing.
For those less God-inclined, do something good. It certainly won't hurt.