^ Or the similar sentiment, what the heck was an 80 year old baboon going to do against a seasoned lion? Why WOULD he go back to the Pridelands for BUT NOTHING, rather than find another full grown lion to go fight a full grown lion?
Rafiki's eccentric, he's not wacked

As for the being in communication with Mufasa thing being a plot-hole......I think this is one of the very SOREST things about the subtlety & beauty of the first one that the sequel Simba's Pride totally degrades and destroys.
In the first Lion King, there really isn't any indication that Rafiki ever communicates with Mufasa
himself at all. Rafiki scents that Simba is alive, finally sees a solution to the Pridelands problem and just happy-joy, goes to find him to fight his fight, and Simba balks. So Rafiki
conjures Mufasa. Rafiki
never addresses Mufasa himself, neither discarnately to gossip OR the large manifestation, his speech is only ever with living Simba. Mufasa has his own things to say and while they may serve Rafiki's purpose, they are meant for his son.
In SP......Mufasa pops up like damn jack-in-the-box in SP and apparently has Rafiki on speed-dial via a Bluetooth earpiece or something because they're always friggin talking to each other chatting and only Rafiki can hear him.
Mufasa's appearance in the clouds was brilliantly & exquisitely handled in the first one, it wasn't a plothole at all until they cobbled together a ridiculously contrived, horrendously conceived ruinous lame/craptastic sequel.
...I THINK I'm done now, LOL.