I can't believe that Kerry-Man would be so forgiving of Chas just because she has cancer. Let's not forget that Kerry and Al were engaged - she thought that he loved her when all along he was sleeping with Chas. And then when he died, Chas acted like her best friend and even suggested that she leave her daughters who might have given her support to work on the cruise ship. Obviously this was because the actress was going on maternity leave, but I don't think she'd come back all ready to forgive for the price of a few free drinks.
At best she'd not hurl abuse at Chas, but she wouldn't be all chummy with her. Contrast that with her reaction to Charity and Mack where Chloe had been the other woman and Kerry knew what a nasty piece of work Damon/Harry was.