DFW Airport Customs and Immigration time

Hey y’all. I’m visiting my hometown during the Christmas holidays with my boyfriend for the first time. We are flying through DFW and have a 2 hour and 20 minute layover before our connecting flight. We are flying in from Japan. Normally I would assume 2 hours and 20 minutes would be relatively alright for customs and immigration, but I’ve never flown directly to Texas from Japan. In addition, my boyfriend is Japanese. I’m worried about how long it’s going to take him to get through customs and immigration. I’ve heard success stories of bringing significant others into the US citizens line, but as we are not currently married I don’t really want to rely on that. Does anyone have any experience on flying into DFW with a non-US citizen? How long did customs and immigration take? Do we have to pick up our bags at baggage claim and go through security all over again between flights? Should we try to find a later flight out of DFW? I tried emailing the airport helpline but no response so far. Any help/advice would be appreciated! Thank you!