If she is married a "father" cannot file a paternity claim unless mother and husband agree.
If the child is his biological child, yes, there should be ways for him to establish that and assert his constitutional rights to be involved in rearing the child.
There should be a mechanism under the various relevant laws to seek a paternity test, but it would require research. There’s more information at https://www.mass.gov/info-details/massachusetts-law-about-paternity-parentage. Service of process to begin a parentage case can be accomplished in a variety of ways when the other party’s address is not currently certain.
