Based on my own FAANG experience managing people with serious illness, it's all going to come down to your manager. My company had great resources to help peop

Based on my own FAANG experience managing people with serious illness, it's all going to come down to your manager. My company had great resources to help people get help and support, as well as a great leave policy. Leaves didn't count as time when factoring in performance (i.e. leaves aren't supposed to hurt you). One team member of mine had a few leaves over the year, including one of 4+ weeks, and still managed to get an Exceeds rating. The massive caveat here is that the pressures of work are still very high, and can (and certainly did here) contribute to and/or trigger illness to begin with. With strong support, one could certainly succeed, but my opinion is that YMMV depending on your manager.