Legally 14 is the age a child can be left alone to look after a younger child for how long you mite have to check . As long as they have emergency contact numbers and procedures put in place theres nothing wrong with it. Have you elderly neighbours that could keep an eye out for you ?

They should be okay if you set expectations. My son is 12 and although fairly hyper at times, can be trusted for hours on his own without burning the house down.

If I am gone for more than an an hour or two I will randomly to check in.

I was always concerned about my eldest boy being home alone for long lengths of time. I was also concerned what other people might think. I shouldn't worry - I guess his wife knows what she is doing.

If they were brought up right shouldn't be a problem. Only you will know ?