Oh my - I am so sorry to hear of your losses.  I was involved in a fire (not my home, and no pets were lost) that was absolutely devastating, so I can only TRY to imagine what you might have gone through!!  
 
 
How wonderful that your daughter was able to take you in, and more, to allow you to get a puppy - after making the suggestion.  A new dog will never replace the ones you loved, but will bring new moments and memories that can help wipe away some of the pain. 
This site rates dog foods:  
Dog Food Reviews - Dry Dog Foods - Powered by ReviewPost 
You can use that to help you make choices about what to try.  The suggestion of getting samples was a good one.  When you get a new food, if using kibble, you can try at first giving it as a treat.  If your dog likes it as a treat, then he might be more likely to accept it as his meal.  I feed Lexi Nature's Variety Prairie and Instinct.  I just got their raw, but haven't tried it yet. 
Good luck, and welcome!  
