Questions about a wip character mod

[Sinoptenyx]

Hello! I'm Sinoptenyx, I was a passive member in the forum 'till I decided to create an account to ask a few questions here.

I'm working on a character mod that adds a different Wendy (with a few different mechanics) and a playable, alive Abigail (both on the same mod). The point would be that they'd be a team and should always stay together, whenever they were too far from each other, their sanity would start to drop, this effect would be negated if they had the bracelets that they made to each other when they were still alive.
 This bracelet would also show their location on the map, kinda like the celestial orb, but only if they were holding it they'd be able to see it, this would make it easier for them to find each other in worlds without global positions, for example.

Basically, those are a few examples, but the core of the question is: Can I make connected characters? In such a way that if one dies, the other loses sanity, and will announce their death, for example?
 Again, I never coded, and I think this is quite a hard start for that, but any help would be well received. Suggestions are welcome too
 Also, if you'd like to help me with this mod (such as coding and sound, the stuff that I still have no idea how to do lol), feel free to contact me on discord (Sinoptenyx#5024)