<human>: Can you condense the text into a few key points?

A little over a month ago my boyfriend bumped into an old friend [24, F] he hasn't seen for 7 years.  They exchanged numbers and went for coffee.  He didn't try to hide this and was open with what he was doing.

Yesterday his phone went off at a wedding and I asked who it was.  He told me it was her, that he was surprised because he hasn't heard from her since the coffee meeting.  That night he went to work and after when I asked how it was he informed me that this girl had stopped by, she was at a restaurant in the area and was headed downtown.  

I thought this was strange but didn't voice anything to him.  At night before going to bed (around 2 am) he checked his texts and I noticed that she was the top one, meaning that he had been texting her fairly late (he had text me saying he was home around 10:30 pm).

The situation isn't sitting well with me.  I have no clue what the messages are about.  Just want some opinions on whether this is sketchy or am I over-reacting.
<bot>: An old high-school friend has been texting my boyfriend late into the night and visiting him at work.  Am I right in thinking this is strange?