I think you're doing the riht thing by not asking him if he misses you etc. He'll tell you he is when he feels ready to (be prepared for that to take time).
In relation to question 1, could you just stop at 'how was the business trip last week'? and leave him to open up? Then you can be positive and supportive; let him boast a bit about how great he is....
Don't be nervous. Your DB success won't depend entirely on this one interaction, and I know it's going to go well in any case!
