Technically he is correct. India would not risk going to large scale war with either Pakistan or China for at least next three decades.
That was the previous Govt's thought process. The current Govt is more than happy to start a war with Pakistan, hence Pak regime toned down on terror attacks in India.
In the event of a war, there will be short-term economic costs such as lower FDI inflows. However, this is nothing compared to the long-term effects of appeasing a terror state. Imagine having a Mumbai-scale terror attack every month and think about how foreign investors will respond to this.
The events of 26/11 were serious enough for the US Ambassador to India having reach out to the Goldman Sachs India head asking about the economic consequences for India for 26/11
Also, historically Indian economy has recovered quickly from wars in the past
GDP growth rate in 1962 - 2.9%
GDP growth rate in 1963 - 6%
GDP growth rate in 1965 - -2.6%
GDP growth rate in 1967 - 7.8%
GDP growth rate in 1971 - 1.6%
GDP growth rate in 1975 - 9.1%
GDP growth rate in 1999 - 8.8%
"A nation which prioritizes wealth over its security will end up neither" - Unknown