when i travelled to china i used this insurance:
Travel Insurance - Columbus Direct (Australia)
but unfortunately it is of little benefit to you as it doesn't appear to operate in the US.. but it does in UK, NZ and AUST.
I think if you are prepared to spend $100+ on your mothers well being by having a phone, you should consider spending the cost of insurance for your own well being. while, as with all things like warranties etc you are very unlikely to need it, if the price is not too bad is it not a bad idea incase something does go wrong. especially if you get sick over there and it is a bit serious the costs can add up very quickly. If your luggage is lost, etc.. these are things insurance can cover.
i worked shorty in the insurance department of my university in australia for staff and students going overseas on university related trips. looking at all the files of things that went wrong and the extreme costs when they did, i think it is not a bad idea to have. once again though it is very unlikely and you probably have more chance winning some money in the casino than having a problem occur.