Dear Donna,
i think it stuck with him that you wanted company and didn't have any. and wanted you to have some even though maybe it wasn't his favorite thing to do. And maybe he felt uncertain about whether it would make much of a difference or not, and so he asked his buds.
I think the choice was out of sense of loyalty and support. That he was torn between doing his own thing knowing mom would be "ok" after all, or going with mom out of sense of love for you and loyalty, knowing you'd be more than ok and enjoy yourself more with him along.
I believe it is a gift to you Donna.
and then, getting out of school... is just a perk.
those are my thoughts.
~ waves ~