Do not worry!!!! My son used to let the girls put nail varnish on him , do his hair etc. He played with the girl's toys. He is now 11 and there is no way he's do any of that now! It was a phase he went through. If you make a big issue of it, he might become anxious.
Of course he wants to play with his sisters' toys, but when he's older, most likely he'll develop different tastes! It wasn't traumatic my son stopping wearing nail varnish... it'd just never ever wear it now!
Most likely these activities won't continue. Let him be who he wants to be right now. There's enough peer pressure out there in the future for him to worry about.... for now he's fine playing with the girls. If he plays with the girl's toys, developing his gentler side, he'll get it out of his system and be rady to move on.
