Please forgive my newbie-ness...

I recently gave my brother a old Sony SVR-2000 Tivo, when he got home (about a 9hr drive) I had trouble talking him through set up because I found out he has IPTV. Currently he says he has a coaxial connection coming from the wall into his cable modem, a network from the cable modem to the IPTV box and then a coaxial cable from the IPTV box into the Tivo input. A coaxial cable then runs from the Tivo output to his TV. He is able to view the guide but it "cannot display live tv" no matter what channel, we have tried rebooting the tivo and channel 4 vs channel 3 settings. When he turns off the Tivo, his can view his cable channels no problem, which seems odd to me.

Question 1: Does this Tivo even work with IPTV? I can't imagine why not.

Question 2: I think he has something plugged in incorrectly, how should IPTV be connected to the SVR-2000?

Question 3: Does he need to change any settings on his TV to get this working?

Any suggestions would be appreciated!