Disapprove has this definition: Verb" have or express an unfavourable opinion. "Bob strongly disapproved of drinking and driving" Disagree has this definition: VERB have or express a different opinion. "no one was willing to disagree with him" ignore the other definitions in a dictionary for disagree where the context is different in the example sentences. Usually you select the top or first definition, then look at the lower definitions if needed because some of these lower definitions will confuse. You should see now there is only one choice of word to select for you CONTEXT after showing you the dictionary definitions it will be best if I throw the question back to you and ask which of these two words should I use for this sentence. Post your answer here and ask for natives and experienced teachers to debate and correct. Only one is correct "for your context"

Disagree means you do not have the same opinion. To disapprove means you dislike something.