D.K.
I would be grateful that he's helping you out. I personally don't see anything wrong with raising boys to be boys. It's not "so 1950's", it actually so biologically appropriate. I hope you don't expect him to try to raise your son to be a girl...
Personally, I am raising my sons to be respectful MEN, not sissy la-las (our family's favorite phrase for the feminization of boys, which I think is a crime). Their wives and children will thank me for it someday.
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Edit: I disagree with the moms that say "don't disagree in front of the kids". It should be "don't FIGHT in front of the kids". Kids DO need to grow up seeing their parents disagree from time to time and also need to see them stay calm and work it out respectfully as two loving adults. They need this example of what a real, strong marriage is like. I think some kids these days are too sheltered and when they reach adulthood, they enter marriage expecting it to be perfect, expecting to never disagree, expecting that their spouse is always going to understand them without having to work on anything, and ultimately they fail. Children need to see that communication in marriage is not static. It is a living thing that requires love, patience and active nurturing. They need to see that making a marriage great takes WORK. I think this lesson is lost too often of late.
Again, don't FIGHT in front of the kids, but disagree and debate in front of them passionately but in control and respectfully, utilizing all of the healthy communication tactics.