I say, and with Allah's success: Wealth is a condition for the obligation of zakat al-fitr, but it is not a condition for the continuity of the obligation. Even if he becomes poor after the day of Eid al-Fitr, the obligation does not fall away; because this right is due in the liability, not in the wealth, so the continuity of the obligation does not depend on the continuity of the wealth. See: Al-Wiqayah p. 229, Umdat al-Ri'ayah 1: 302, and the acceptable comments p. 198, and Allah knows best.