Yeah, he'll be fine...
Probably the can is lacquered and doesn't digest. It ought to be aluminum, so it should corrode pretty quickly in stomach conditions. So, maybe nothing, maybe pitting, probably not total dissolution. I'm not sure what hybrids all use inside; the polymer part anyway, might not be toxic, I think it's pretty much just going to stay together through the process?
And, copper leads, the tin plating might tarnish or something, and the plastic base brackety thing, fine of course. So I'd expect it to largely remain together.
The awkward shape, of course could always lead to complications, but it's most likely fine. Heh, growing up, a friend of mine accidentally swallowed a roofing nail.. did nothing, fortunately.
As for electrolyte part if any, dunno. Haven't seen an SDS for anything like that. I want to say several things wouldn't be too bad, but there could well be something nasty mixed in there from time to time. And I may be underestimating the polymer electrolyte part.
Tim