How Young Is Too Young?

There is a situation in my neighborhood that is causing me some alarm- not a great amount of alarm but enough that I find it somewhat troubling so I am turning to the smartest ladies I know to see if I am being a little too....well, too Toni.

My neighbors have three children: an 8 year old (Rachel), a 4 year old (Caleb) and a 20 month old (Sadie). Rachel and Claire are good buddies. Rachel lives with her dad and stepmom and Caleb and Sadie are their children. Capisce?

Well, the dad, who I'll call Steve, is a nut about his yard. I mean, a crazy man. He mows several times a week and doesn't like for the kids to play in any area that is not outfitted with play equipment because it smushes the grass. (Honestly. This is not a lie.)

Steve's wife, Amy, a hair stylist, works every other Saturday, thus leaving the kids alone with Steve. This is where Steve's lawn obsession becomes my problem. Steve mows while leaving the 8 year old in charge of the 4 year old and, worse, toddler Sadie. Now, as a SAHM, I get that sometimes things need to be done and when you have an older, more responsible child, they can really fill a void. There are many, many occasions where Claire has to step up and help with Liam. I get that.

She distracts him while I pee. She takes him to the basement while I make dinner (remember I am not a cook so this is usually a microwave warm up of leftovers) but never is she in charge of him for any more than a short while. I just don't see this as her job or responsibility and she is only 8!

A few weeks ago, Steve mowed (twice, as is protocol and takes about 2 1/2 hours) and then cleaned gutters, power washed the house and sprayed weed killer on every weed lining the street in our neighborhood (again, not a lie.) and this took a total of about 6 hours. I know this because we were outside the majority of that time.

While Steve was doing all this, Rachel watched, changed, fed and entertained Sadie. Claire and a couple other neighborhood girls played for a while but, once I realized Rachel was the one in charge, I insisted Claire return home. Rachel eventually had to take Sadie inside the house as it was really hot and the baby was cranky; a neighborhood girl accompanied her. I felt uneasy about this girl going inside alone with Sadie and Rachel because I am good friends with her mom and it made me uncomfortable to think of two 8 year olds watching a young toddler. I chose to butt out.

Well, of course, Sadie got into markers and marked all over herself and a wall. When Steve learned of this, he freaked. He screamed (according to the other girl in the house) at both 8 year olds and grounded Rachel from the computer (where she and her friend were playing and NOT watching the tot) for life! and made her clean the mess.

So, now I don't know how to handle this. I don't want to cause trouble but I am uncomfortable with letting Claire play at their home when the mom is out. I feel that Rachel has way too much responsibility at too young an age. Am I completely overreacting by making the rule that Claire may not, under any circumstance, be alone inside with Rachel and Sadie?

Is this just me being irrational and over the top, or not? At what age is it appropriate for an older sibling to watch a little one? I babysat at 11 but I was a strangely mature 11. What do you think?