Gosh I dont' think you're negative at all! I would have done the same. Especially being 20 mins each way, you'd have to be gone for at least an hour.
I leave DD 10 home for 1/2 hour while I pop to the shop. It is 2 mins away and she usually calls me while Im out!!! (cute). But I wouldn't leave her if I was going any further.
I can't see that being responsible could be taken as negative. MIL's can be soooo frustrating. She's prob annoyed because she came across looking so uncaring!! xo
Thanks for understanding. I feel so much better with myself now that I have had everyones opinions on this, so glad I posted my concern. MIL is still being very nasty to me. I did say in a kind manner that I wouldn't interfer or say anything if she had left him home at her place. But she did put me in a situation that I was really uncomfortable with. I'm sure his mum leaves him home alone due to the fact he knows his neighbours and they do live in suburbia where its busy, also he knows his surroundings.