Serious question. I tried /b/ first but nobody could help.

I have a male friend online. Nothing he's said in the past seemed dishonest, but recently he started claiming that he breastfeeds his sisters child because she can't. He claims that he can fully express milk and that it's actually nutritious for the baby. I've heard of sympathetic lactation, but is this actually possible? Note that he is NOT a tranny though quite feminine, and apparently didn't take any hormones to do this. Has he lost the plot and he's now making up stories, or is this actually possible?