First, SFFA is term of art for FATCA under §6038D and is not relevant for FBAR, although there are overlapping reporting requirements.

What US address are you referring to?  I presume that account is in a foreign country and the trustee should have a foreign address although your client may be in the US.

If this is a foreign pension account, there's a lot more you should worry about.  There could be foreign grantor trust and PFIC issues that require disclosure, reporting, and could have substantial tax and penalty exposures, depending on whether the arrangement is covered by a treaty provision.