Should I let my boyfriend have his space?

My bf of almost 9 years told me last night he needs time apart. Let me start off by saying I have been fighting cancer and have a few life threatening surgeries. He’s stuck by me thru every single one. He was there every day. When I came home , he changed my wound vac, my iv, made sure I had my meds and took care of me. I felt so grateful and blessed to have a man care so much about me! Now, he’s not the same. He’s angry, depressed and ignorant, all the time. We have not been intimate often because of my cancer. I know that hurts him. Says he doesn’t feel like a man anymore. He’s mean to my girls (that are grown adults) even his own kids. No one wants to be around him. I’ve asked him to get some therapy and maybe meds to help him get thru what I think is ptsd from everything that he’s watched me go thru, and helped me get passed. Question is, do I just walk away and let him have his space, or stay and force him to get help and see if we can work it out? I’m so shocked and confused that he wanted this at all. We otherwise have had a great relationship . My heart is broken and I don’t know what to do!