I say, and with God's success: He must go out for jihad if the call is general. If he spends a portion of time leaving his worship even if he is forgetful, it invalidates his obligatory worship which is the vowed one, and he must make it up. This is different from leaving for a person's need; because it is known to occur and thus is exempted. As for the confirmed Sunnah and recommended worship, it ends with his exit without an excuse.

Refer to: Al-Taybin 1: 351, and God knows best.