Husband Recently Diagnosed w/ Signet Ring Cell Adenocarcinoma Stage 4

My husband recently had to have emergency surgery 12 days ago because his colon ruptured and has since then been diagnosed w/ Signet Ring Cell Adenocarcinoma Stage 4 four days ago based on pathology results from the part of the colon that had to be removed. The oncologist said she thinks his cancer originated in his abdomen and spread to his colon and the tumor is what caused a blockage is the reason why it ruptured. Further endoscopy by his GI found that he also has esophegeal cancer now. We are both in shock and devastated since this has all came about very suddenly and unexpectedly and seems to be spreading so fast! He's 68 years young and was never sick a day in his life before our son passed away and was diagnosed with  IBS, IBD, UC, Chrohn's shortly after our son's passing which his GI said was likely brought on by stress. Anyways, he's got an infection now that they think is from surgery and are trying to get it under control and say he won't be able to start any chemo treatment until 4 weeks after he can finally begin to heal from his surgery. I haven't been this scared since the day our 27 year old son nearly 6 years ago was diagnosed with sudden onset of AML Leukemia after he had oral surgery and wasn't ever able to heal. Our son was diagnosed and we lost him 3 weeks to the day after he went to the ER. I've gone through the loss of both of my parents to lung cancer within 3 years of each other and that was the hardest thing I'd ever had to endure before the loss of our son which I'll never get over, but I had finally learned to accept and live with the horrible loss of our precious boy over the past 2 years, only thanks to my husband being there to help each other get through it. I've been trying to keep him and I both as positive as possible, but I'm feeling so helpless and hopeless and terrified right now, so much so that I can barely function physically today. Somebody please tell me there's still hope that he can pull through this even though it has already spread so fast as the thought of losing him this soon is unbearable! I'd really appreciate any positive input regarding others experiences with this type of cancer. My husband's a fighter and really wants to beat this and refuses to give up and I know in my heart if it's up to him he won't leave me anyime soon, but watching him suffer is absolutely killing me!