Here both 𝓟 and the 1830 edition agree in having the plural them, so very likely 𝓞 also had them. The plural them refers to the generic he that occurs earlier in the sentence: “whereby he that is found guiltless … hath it given unto them to dwell in the presence of God”. In his editing for the 1837 edition, Joseph Smith decided to grammatically emend this instance of the generic them to him. Here the original text itself may have read “unto him” since the scribes sometimes mixed up him and them during the dictation, which is not surprising given that in unstressed contexts both pronoun forms are pronounced as /ßm/ (see under 1 Nephi 10:18–19 for two momentary mix-ups in 𝓞 between the two pronoun forms). On the other hand, there are quite a few cases where the original text shifts the grammatical number for generic pronouns within the same passage, as in the following two examples where one could interpret the them as a mishearing for him:
There are other cases where the issue is between their and his, which are phonetically dissimilar, as in the following case:
In other words, there are cases where the switch in number appears to be fully intended and not due to mishearing. (For other examples of such switching in number for generic pronouns, see under 1 Nephi 17:48.) Thus the critical text will accept the switch in number for the generic pronoun here in Mormon 7:7 and restore the earliest reading since it is possible. Of course, the alternative possibility remains that the them is a mishearing of him (just as it could be in 1 Nephi 10:19 and Mormon 9:21, listed above).
Summary: Restore in Mormon 7:7 the plural generic pronoun form them even though the preceding generic pronoun in the sentence is he; such switches in grammatical number can be found quite frequently elsewhere in the original text; nonetheless, there is the possibility that the them in Mormon 7:7 is a mishearing for him that entered the text as Joseph Smith dictated it to Oliver Cowdery (here the presumed scribe in 𝓞).