I would ask him exactly what "having a future" means. In fact, every time I see someone write about how perl is dead or dying I really have no idea what they are talking about. Let's say all development on perl stopped today. Does that negate the usefulness of the tool? Will all of the binaries suddenly disappear? Will programs just stop working? No, no, and no. So even if there were no active development perl could still enjoy a relatively long afterlife.
Yet perl continues to have an active developer community. Does he think otherwise? Point him at the perl5-porters mailing list, and all of the activity surrounding perl6. Point him at the perl foundation and at the YAPCs and at the annual Perl conference. Point him at amazon.com and yahoo.com and the other major sites that continue to use perl. So, what constitutes "no future" exactly?
The only reasoning I can think of why people think PHP has a future and Perl doesn't is that Perl has implemented most (if not all) of the useful features extant while PHP still has yet to implement some language features. Ergo, PHP has a future (there's still stuff to be done) and perl doesn't (we've already done it all). :-)
