Going to post this here since the thread got locked before I could reply.
I think it's dumb to accuse Togashi about lying about his health, we know a lot of these mangaka especially the ones that do weekly shonen jump do go through health problems.
And I personally don't see Shueisha allowing a healthy Togashi take very long breaks.
As for why doesn't get someone else to the art, well they tried that and didn't work. Others did offer to help him by doing the art while he does the writing but Togashi refused.
Togashi does seem a bit stubborn as he really wants to do both the art and the writing.
Also here is a statement from Togashi about how severe his back problem was.