I say, and with God's success: Whoever has an excuse should perform ablution for each prayer separately, and it is not sufficient for him to use the same ablution for two prayers, unless he performs ablution and prays, and nothing exits from him until the time for the other prayer enters, and he is able to pray before the excuse exits from him; then his prayer is valid, because he is not considered a person with an excuse in this case, as a person with an excuse is one who prays while the excuse is present. And God knows best.