can a family member send my boyfriend to jail for statutory rape if he is only 33 months older then me if I was pregnant? When we had sex it was consensual?

Yes, a family member or anyone can file a complaint if they think a crime has been committed.

If he is 17 or 18 and is engaged in a sexual relationship with a minor under the age of 16, he can be arrested and face charges.

In the state of Washington, a minor is not legally capable of consensual sexual contact with another until they are 16 years of age or older. In other words, it doesn't matter if a 14 year old consents to a sexual act; the law says they can not. This means that the 17 or 18 year old could be in trouble legally.