No way to know if he'll get sick or if he already is, but yes, 75* is too low. If depending on ambient room heat, you'd want about 85* for BPs so they stay
healthy. If you decide to adopt him, listen close to his breathing (for whistles, clicks, crackling that may indicate an RI), and look for bubbles in mouth, or open-
mouth breathing, & any other health issues, since a snake immune system doesn't function well at lower than optimal temperatures. Hope you get to him in
time...I wonder how long he's been this cool or coolerl? In the wild there are temperature fluctuations too, keep that in mind.