I am sorry to hear your mother isn't doing well. While private paying, the VA will contribute up to $1,149 per month. Once on Medicaid in a nursing home, it is reduced to $90 that Medicaid cannot touch.
The VA will pay what they call "Aid and Attendence" to any vet or the wife or widow of a Vet who served in the military during a wartime. As long as your mother was married to your father at the time of his death and never remarried. The max amount is around 1,100.00 and depending on her net worth that will determine how much she can get. Call your local VA for more information. The only problem is that this process can take one year to complete. They do pay retroactive payment though. Again, ask for information about Aid and Attendance for widows of vets. It is for a person who can no longer take care of themself and needs the aid and attendance of an other person. I applied for this for my mother and it has been very helpful. Good luck. May God bless you and your Mother.