As explained under 1 Nephi 7:5, the Book of Mormon text consistently refers to a patriarch’s “whole household” or “all his household”, such as twice here in Ether 13:20–21. In the first instance, however, Oliver Cowdery initially omitted the all, but later he supralinearly inserted it, probably when he proofed 𝓟 against 𝓞 (the level of ink flow is somewhat heavier, as it is with the supralinearly inserted that in verse 18, discussed above). In this particular case, the all here in verse 20 is extant in 𝓞, so we can be sure that Oliver was not emending the text when he added the all. (The second all, in verse 21, is not extant in 𝓞, but it was undoubtedly there.)
Summary: Maintain in Ether 13:20–21 both occurrences of all in the phrase “all his household”, the reading in each case of the earliest extant text.