Well yes, it was weird that he was touching your thigh, the only way it would be 'excusable' is if he has also been asleep and perhaps thought it was his girlfriend's leg he was touching. Though I doubt, that is the case.
I think it definitely needs to be addressed. Mainly because you don't want your friend dating a boy who would try it on with other girls.
It's worse that she was there at the time and that he tried this with a friend of hers - imagine what he is like when he is out with friends and around other girls.
Your friend may be angry with you at first, it's just the way us females react, but I am sure she will thank you for being a loyal and true friend eventually.
Boys will come and go, but friendship can remain all your lives. It is best that she hears this from you now that from him when they break up.
It's worse that she was there at the time and that he tried this with a friend of hers - imagine what he is like when he is out with friends and around other girls.
Your friend may be angry with you at first, it's just the way us females react, but I am sure she will thank you for being a loyal and true friend eventually.
Boys will come and go, but friendship can remain all your lives. It is best that she hears this from you now that from him when they break up.