Re: daycare providers -- how do you do it?
I don't wear my 4 month old much, nor is he a great sleeper during the day (or night), but he is usually a fairly chill baby who loves watching his brother play. Mostly, he is having to adjust to the schedule of my two year old, not the other way around. I don't feel like I can take him into a dark quiet room for an extended period of time to get him to sleep unless the two year old is napping. So, if we are in in the living room with the train tracks, he is there with us - either I'm holding him or he's just laying around on the floor watching us. If the two year old wants to walk around the house pretending we are firefighters, I carry the baby around. I guess what I am saying is that I still spend more time playing with the toddler, and I don't worry a lot about "playing" with the baby except to offer him a teacup when we're having a tea party and talk to him a lot.
I'm with the others on the payment thing. Unless your brother is in dire financial circumstances, they should be paying. I'd probably use some of the payment to get a cleaning person every other week, because it is not realistic for you to get a lot of real cleaning done (or organizing/decluttering!) in addition to caring for 3 kids, a baby, and cooking.