"Healthy" has always been an actual word, while "helpy" hasn't, so no wonder it's grating!
I'm all for language changing when it makes sense. I can't think of any situation where using "healthy" instead of "healthful" obfuscates the meaning in any way. Same with "who" and "whom." "Whom" and "healthful" could disappear and nothing of value would be lost. But when it comes to things like "literally" meaning "figuratively," I mourn the loss of utility the word used to have.