All good, OP. Maybe we should plan a sleepover with our two DD's and they can keep each other entertained throughout the night
DD would love it. The times we've tried to put her to sleep at my sister's house on niece's trundle, DD just wants to party. Niece gets upset and wants to sleep Our two would have a ball

...He might have been doing it for attention, in which case he got attention. Just like if he was hungry i'd give him food! He seemed genuinely upset to me and he eventually stopped doing it (3 months maybe).
That's such a good perspective Lenny. I hadn't thought of it from that angle.

Pac, I think you're doing a wonderful job responding to her needs to the best of your ability.