Is there a more masculine version of "nanny"?
Solution 1:
Keeper, noun
A person who manages or looks after something or someone.
Caretaker, noun
A person employed to look after people or animals.
Optionally, the child could describe Alfred as his "parent's assistant," or more wordily his, "parent's assistant who looks after me."
Solution 2:
The British Home Office uses "au pair" for both males and females.
This has been the case for about the past 40 years. Note the use of the gender-neutral "they" at the official website: https://www.gov.uk/au-pairs-employment-law/au-pairs