I take care of my brother who is fully functioning, but can’t get himself meals, is there anywhere I can go to get in home care for, so I can leave town 4-5 days occasionally?

Door Dash, Uber Eats, Meals on Wheels, TV dinners, microwave meals

In some areas Meals on Wheels will deliver food and do a wellness check. Call your Area Agency on Aging and see what services they offer.

There are caregiver agencies through which you can hire temporary in-home care. It's expensive. Does he have his own income to pay?

Or he can order through Doordash or Uber Eats or Instacart.

Or he can learn to handle his own meals.

My husbands Aunt spoiled her son. He lived with her and held down a job. She went on a month trip with my MIL. She bought plates with sections. Cooked food and put dome on each plate. Had hashbrown in baggies. All he had to do was take the plate out of the freezer and heat up in the microwave.

Your brother is not able to make himself a sandwich, scramble some eggs?

I know this may sound selfish, but I would not give up my life for a brother. I love them, but would not care for them.

I do not understand how a person that is "fully functioning" can not get a meal.
What do you do for your brother other than provide a meal. You say you take care of him. Is that all you do, fix meals?
You can get a caregiver to come in daily and fix a meal.
You can make meals in advance and freeze them. (or if you are going to be away for 3 or 4 days you can portion meals and leave them in the fridge)
If you contact an Agency they will assess him for the care that he needs and a caregiver will be assigned.

Adding to your profile or adding to your questions would help a LOT

You are saying he is functioning but cannot get meals?
That isn't computing for me.
Microwave meals today are quite simple. There is also delivery of nutritious meals from meals on wheels type agencies which you can call your local senior centers and your local council or agency on aging about.

I think if he is able to contact you easily and you are not too far away, that your making pre-cooked means for him to heat up, soups and such simple things, given how little we need to sustain ourselves when elderly should work.

IF that is the only issue. And usually when that issue is on the table, some others are as well. You may need a wellness check done, and in that case it would be someone stopping by, heating dinner and etc. You could contact care.com and so on.
Or friends! It's always great to call them in.
Good luck.

If your brother is "fully functioning" can he not put some frozen dinners in the microwave or frozen pizza in the oven while you are away?
Or can he not order online food from the restaurant of his choice to be delivered?
Your post is confusing as how can a "fully functioning" person not prepare for themselves their own meals? Makes no sense.
You might need to fill in between the lines so we can better help you.