[sarah]

I'd ask your doctor about anti-depressants. I found I suffered severe mood swings and my tolerance level was low. I was impatient about petty stuff.
As a supporter in a cancer support group here, I have seen caregivers who were fantastic, others who were overwhelmed and some who couldn't handle it. We've found it most difficult to help male caregivers but had some success finding other male caregivers who were just willing to go out and do something with them - distract them.
As others have said, men want to fix stuff and when they can't, they are frightened.
Be patient, find out about anti-depressants and realize that everyone's world has been turned upside down but it will end and get better.
take care, watch some funny movies or sitcoms and laugh.
hugs and love
sarah