Umm... one of the questions that's been asked is whether his iPad will connect anywhere else, If it will, the issues is between the iPad and the particular configuration he has at home. If not, the issue is with the iPad.
Since we don't have an answer to that question yet, your inference that anyone is telling him to "phone ahead to every business or hotel he plans on visiting to request that they replace their "clunky old router" " is unjustified and unhelpful.
Please, continuously blaming every ipad wifi issue on the same router that happily works with every other device is getting old. What standards does iPad support that these clunky old routers do not?
Since, as you've said in another post, you're experienced in the ways of the internet, you will know that it's quite common for new kit to have problems connecting to old kit.