Can MetLife use a pension from a previous employer (not the employer the DI policy is received from) as an offset to reduce my benefit?

My husband has been on Metlife DI for nine years. He will be 62 this year and has an opportunity to begin collecting a small pension from a previous employer (NOT the employer that provided the DI but one he worked for from 1974 to 1993). We would love to begin receiving it. There is no financial advantage to waiting to age 65; the dollar amount does not increase. My question: Can Met use this as an offset and reduce his benefit? In that case we would actually be worse off because his Met benefit is only 50% taxable while the pension is fully taxable. The booklet from Met addresses this but in such legalese that I can’t be sure. It refers to “the Employer” (capital E) as being the one who provided the DI and states that any retirement benefit from them would be an offset, but he doesn’t have anything from them, wasn’t there that long. It would seem a separate, private pension is none of their business but they seem to think everything is their business. I am reluctant to call them because the offshore people are not easy to communicate with and I also don’t want to incur their scrutiny, especially after seeing all the comments on this site.