Losing my mind

I see my mom in the hospital totally wiped out by the high doses of radiation they are giving her and just a week ago they told us they were just making her comfortable. She can't have radiation on her liver, which is where some of the tumors have gone to, along with other spots of her body. She is 70 yrs. old and I can't bare to see her in pain.  We lost my brother in Dec. 06 and he was only 38.  Why is it legal to put animals out of their misery and not for humans whom we love. We must watch them suffer until the disease takes them. This is not right......it is down right cruel, Does anyone else see it this way?