Men can not produce milk with which to breastfeed infants.
However, infants often suckle their father's nipples in the Aka Pygmy tribe in central Africa. The Aka fathers "are within reach of their infants 47% of the time". This was studied by an American anthropologist named Professor Barry Hewlett. REF: https://www.theguardian.com/society/2005/jun/15/childrensservices.familyandrelationships