To be fair to BF, he has offered solutions, albeit in the most obnoxious way imaginable.
1. 5GB is enough for anyone (even when the OP already stated that he'd bought extra storage)
2. Buy more storage (for every family member, presumably)
3. Use a Mac (quite a significant expense for just for storing photos)
Though since the question was about whether family sharing would allow aggregating of any purchased storage, god only knows why he was offering a hodge...