“tritium breeding from fusion is a losing proposition [you get back fewer tritium atoms than you start with]. So, this MIT geology professor lied.”
No. Be-Li blankets can make reactor self-sustaining.
No. The math doesn't work out, actually. It gets you close to 1 Tritium bred per fusion created, but it assumes 100% of neutrons go to breeding and it assumes no losses due to hydrogen diffusion into metals, pump losses, etc.