Direct Speech: I said to my friend ,"good morning. Let us go for a picnic today.
Indirect speech(book answer): I wished my friend good morning and proposed that we should go for a picnic that day.
I think there should be they instead of we.
Direct Speech: I said to my brother,"Let us go to some hill station for a change".
Indirect Speech(book answer): I suggested to my brother that we should go to some hill station for a change.
In second example too book uses we. I read a rule saying when we change speech let us change into they. So which one is correct we or they?