She probably isn't 'boasting' but just drops it in to the conversation... Been out with a group of friends tonight and she was there - I deliberately don't see her that often anymore because of stuff like this!
I moved my daughter to a different school to get away from Mum's like this. DD is who she is, she's good at some things not others, she get invited to some, not others and so on. Do I want to compare her to yours... err no thanks - she's my daughter, I will win that argument!
I have an ex friend who is exactly the same. I made the decision to distance myself when it emerged ds had mild SN and she continually compared his speech (at 2.5) with her 12 month old. I suddenly realised her little boasting jibes were actually cruel as well as irritating and cut all ties. I still have to see her occasionally but don't allow her near ds!
I would say end the friendship ILIC, however as it seems an important one then I should be ready to ignore it by having a little tally of the times she does it in a meeting and just think to yourself 'there she goes again'! I would actually feel sorry for her DD; if comes down to what label you wear it is pathetic.