Your client is filing MFS.  The spouse's info is NOT needed on Sch CA(540NR); therefore, Column for "Spouse" would be blank.

(Your client's filing status is also MFS for CA.) 

What do you mean by "there is all kinds of income"?  If the Spose has CA source income and has to file a CA 540NR, Spouse will file as MFS and Spouse's info will be under "Yourself" on Spouse's Sch CA (540NR).  On that return, your client would be the "Spouse" (and the column under "Spouse would be blank - i.e. your client's info would NOT be needed).  On that return, your client's spouse would be the "Yourself"