It might be one of the house - elves. They are used to taking care of others and serving in the wizarding world. So an elf like Dobby or Winky could be the one feeding Harry. They would probably be very efficient at it, making sure Harry gets all the nourishment he needs while also keeping him clean and comfortable.
Maybe it's Dumbledore. In some fanfictions, Dumbledore is portrayed as a very father - like figure to Harry. Feeding Harry from a bottle could be a way of showing his deep care and protection for Harry in a different, more nurturing way than we usually see in the original series.
It could be Hermione. She is often portrayed as a caring and nurturing character. She might take on the role of looking after Harry in a situation where he needs to be fed like a baby.
Well, it might be a really strange and cute fanfic where Harry, perhaps as a baby or in a vulnerable state, is being fed a bottle. Maybe it's a story about taking care of a young Harry in an alternate universe where he's not in Hogwarts yet.
It could be a Death Eater in disguise. They might be trying to get rid of Harry once and for all to please Voldemort. They could have slipped the poison into his food or drink when he least expected it.
His friends from Hogwarts, like Ron and Hermione, are likely to help. Ron could bring his family's practical knowledge of wizarding homes and Hermione would contribute with her extensive research skills.
The doctor could also be a Muggle - born wizard who has combined Muggle medical knowledge with magic. This kind of doctor would approach Harry's situation from a different angle. They might use Muggle - like scans enhanced with magic to look for internal problems. They could offer a fresh view on how magic interacts with the body, which could be very helpful in diagnosing and treating whatever is wrong with Harry.
Harry could encounter a group of wizarding surfers. They use magic to enhance their surfing experience, like creating perfect waves or making their boards fly over the water. They introduce Harry to a more laid - back side of the wizarding world in California.
He might meet the future versions of his friends like Hermione and Ron. Their children or grandchildren could be there, and they might have different personalities and magical skills compared to their predecessors.
It's possible that an old acquaintance from Hogwarts who has family ties in America could assist him. This person might already have a network in America and could introduce Harry to important people. Also, there could be some reclusive magical scholars in America who, out of curiosity about Harry's powers and his role in the UK, decide to help him. They could teach him new magical skills that are specific to the American wizarding world.
Harry could meet some local magical creatures that are unique to Africa. For example, there could be a magical creature similar to a hippogriff but with different characteristics. And he may also meet African witches who are experts in herbal magic, which they use to heal and protect their communities. They could teach Harry some of their techniques and knowledge.
Dumbledore might help in a spiritual or advisory way. Even though he's passed away, his wisdom could be passed on through memories or some magical means. Also, Hagrid could be a great help. He could assist in building areas suitable for magical creatures with his love and understanding of them.