As a Transman, I think I'll chime in on this matter...
If the gentleman in question has been on testosterone for more than 5 years without any long period of time off testosterone, his odds of pregnancy are pretty much zero.
The eggs pretty much shrivel up
Most Transman who are wanting to carry need to get off testosterone within the first 3 years or the odds become very slim and risk of complications becomes greater.
An internal ultrasound will give a very clear answer as to how the ovaries look
I know this from personal experience, also working in the largest LGBTQ health clinic in the country.
On a personal level I have never been pregnant since starting my transition and I only bareback...
I hope this information helps.