Remote PREV button not working

Hi.  Today my dad called and said the PREV button on his DIRECTV streaming remote doesn't work now.  For the past couple days, I had been troubleshooting a different issue with DIRECTV and they had me reset the receiver, set it back to factory settings and all re pair the remote several times.  Yesterday I had to get it working with controlling the volume up and down again.

But, today he's telling me the volume is working.  However, the PREV button doesn't go back to the prev channel he's watching.  Apparently it just stays on the same channel.

I really don't want to have to reset and re pair a bunch of stuff since its his equipment and he's elderly so he doesn't understand a lot of the technical stuff.  I think he may have another remote so I can try that next time I'm over there.  

Is there anything else that I can troubleshoot?  I'm getting gun shy about doing anything any more, because when I do it's like something else stops working and he gets frustrated.

Thanks,
Gary