My dad is fighting brain cancer and mom is struggling.

So at the beginning of this year my dad began to deteriorate. Dad is a tough patient and he hates going to hospitals. We begged him to see a doctor. He was not listening till we finally got him to a local hospital they did a ct scan and found a tumor 4 days later he had the operation to remove 80 % of it. He has now been treated with radiation and chemo for the last month with 8 treatments left. The last 3 weeks its been really hard as the chemo has lead him to have severe swelling and weight gain. Sadly his mood has been very bad with him rudely treating mom his caregiver especially on days I am away from home. Mom is diabetic and she has emotional swings as well. And now with his mood and her own issues I am at my wits end. I am trying to find out if he would better off with a caregiver to help her. He does have excellent insurance I am not sure they would cover it. Was wondering if their are support systems to help. Any ideas.