6 month old prem daughter being criticised for development speed ?

[Mumlife1]

My partners sister has a baby that is 3 days older then my DD , my DD was born 6 weeks prem and is now 6 months old. Her cousin (my partners sisters child) is definitely more advanced in certain things then her (due to her being premature) and his sister takes it upon herself to point out and CRITICISE my daughter for not being " as capable " as her son.. this obviously makes me angry beyond words and my partner also but he refuses to say anything as he doesn't want to cause a family feud ? Has any one else had anything like this? Is my partner right to say we should just let it go ?

Just ignore. Reply with "They all do things in their own time" or "It isn't a race".

I think it is fairly natural to compare, when you have little ones so close in age. the issue is that she hasn't got much tact. I think 'criticise' is a bit of an emotional word. Just relax and enjoy your little one and the steps she takes and the progress she makes. They all develop so much and so quickly when they are little, but it all comes out n the wash. Just don't let her get to you.
Go out and mix with lots of people. You'll see how they are all different.