So, I read somewhere that you could use DebugEnabler to change relationship status between Sims. However, no matter where I search, I can't seem to find the control. Would you happen to know where in the menu I could find that, or, alternatively, if a different mod needs to be downloaded to do that? Thank you!

The mod that we recommend to change relationship status is MasterController, not DebugEnabler.

If we are talking about changing their friendly score towards each other,
NRaas > MC > (Sim) > Intermediate > Long Term Relationship: By Value

If we mean the category of friendly, unfriendly, or romantic relationships,
(same menu) > Long Term Relationship: By Category (e.g., best friend, enemy, fiance, spouse)

If we mean actual blood relationships (parent, child, sibling)
NRaas > MC > (Sim) > Advanced > Family > Add/Remove Parent/Child/Sibling
(MC Cheats add-on module required for this one)

I put "(Sim)" in parentheses up there because it depends on how the commands are invoked. If you click on a sim, the mod understands that to be Sim A and will then ask you who should be Sim B. If you click on a lot tag or City Hall, etc., then you are prompted to select first Sim A and then Sim B.

There may well be a DebugEnabler way to do this in there someplace, but those are EA commands that the developers left in the game with no other way for us mere mortals to get to them and they are undocumented. Some of them are just plain broken. Generally speaking, if there is a MC or another way to accomplish the same thing, it's safer to do it the MC or other way. Not that DE isn't at times helpful too, but it's not the mod one would reach for first in this kind of instance.