There may be financial help available from local social agencies but I don't know where she lives so its a little difficult to say? If it were in my commnity, I would suggest calling 2-1-1. Its a referral agency of every helping agency available, including ones that offer financial help to the needy. Here is their website:
www.211.org. Otherwise, I would try an actual hearing aid business and ask them if they know of any financial aid possible. It is nice of you to help your friend. Thanks for posting and good luck.