Is the Umrah, which he interrupted by first exiting the state of ihram and then re-entered ihram for a second time from the Mosque of Sayyidah Aishah, valid, and is another fidyah obligatory upon him?

A person in a state of ihram does not exit it merely by wearing sewn clothes or by revoking the intention. Rather, exiting ihram occurs through three means: completing the rituals, or performing tahallul (exiting ihram) if a condition was stipulated and met, or being prevented (from completing the rituals).

So, if one is unable to complete their umrah and puts on their clothes, they remain in a state of ihram and do not need a new ihram.

If they complete the umrah, they have exited ihram, their umrah is valid, and they owe a fidyah (expiation), which is fasting for three days, or feeding six poor persons, or sacrificing a sheep.

If they return to their country before completing it, they remain in a state of ihram and are obligated to return to complete it. If they are unable to do so, they are considered "prevented" (muhasar) and exit ihram by sacrificing a hady (a sheep or one-seventh of a camel) and by shaving or shortening their hair.