- 他比妻子更爱他的母亲 (he compare to his wife, he loves his mother more) means "he loves his mother more than his wife does" and it is not what the English sentence means.
- 他爱他的母亲胜过爱他的妻子 is correct but wordy, you can reduce it to 他爱(他的)母亲胜过爱(他的)妻子 --> 他爱母亲胜过爱妻子
Replace 胜过 (better than) with 多过 (more than) --> 他爱母亲多过爱妻子