Does anyone know of a home health agency that has shorter shifts?

you are going to have to contact several agencies. the shorter shift ones may be there, it depends. Where I am, Long Island around Northport, I only found a couple that seem to have short hours possible. However, in all fairness, I don't think I'd want to haul them out for only a half hour of work. You mention 2 hours, I think there are some who could do that but you have to call everyone.

I agree with cwillie, you would need to call all the caregiving agencies in your area. The agency I use for my Dad recently changed to allowed shorter shifts, but it doesn't mean other agencies under the same name will do the same.

Curious, who does the cooking and housekeeping for your Dad? Or do you do that?

Elaine, we are caregivers from all over the country, in fact, all over the world. Start by calling all your local agencies, I know it is time consuming but will give you better answers that polling forum members.
BTW, where I live (ontario, canada) often support workers are expected to prep and serve a meal, shower and dress their care recipient and magically transport themselves to their next appointment all within an hour... be careful what you wish for!