Regarding section 148

In order to issue a notice under 148 there should be reason to believe....based on the verbal statement made by your client if the assessing officer is able to prove that income has escaped assessment then it may be valid notice
...as the assessing officer has to record the reasons before issuing notice and reasons can be demanded by your Client on filing the return u/ s 148

First ask your client to file ROI in response to 148 notice and after that request for reasons recorded by AO. If you believe that the AO does not have any tangible material to gain reasons to believe than the validity of 148 can be challenged

I agree with the experts, there must a reason to believe the facts in your case.