Approve "Ask to Buy" without an Apple device for the parent.

Several years ago I set up an iCloud account for myself and my child, with my child as a member of my family. I no longer have an Apple device and he has an iPhone 5s with the latest OS (11.2.6). He cannot install any apps without my approving them, but I have no mechanism to approve them without an i-device.

Is there anyway to approve "Ask to Buy" requests without the parent having an Apple Product? I don't see a way in iCloud? What if I install iCloud on my Windows PC? If not, can I transfer him out of the family (he is under 13) or to someone else? Again, I don't have an Apple device.

I've logged into my iCloud on the web and checked the email address associated with my iCloud account but see no evidence of the request.

I tried to sign into iCloud on my child's device, but that essentially resets the phone so I am hesitant to of that and it is not an ongoing solution.