  We address the consequence of invisible neutrino decay in the context of two
long base-line neutrino experiments; T2HKK (Tokai-to-Hyper-Kamiokande-to-Korea)
and DUNE (Deep Underground Neutrino experiment). The main purpose of this work
is to bring out the aspects of CC (charged current) and NC (neutral current)
measurement at DUNE in the context of invisible neutrino decay. We find that
the inclusion of NC measurements (NC) at DUNE with the charged current
measurements (CC) enhances its ability to constrain invisible neutrino decay.
This enhancement further increases if the total run-time changes from 7 years
to 10 years at DUNE. The synergy between DUNE and T2HKK improves the
constraints on invisible neutrino decay. The derived constraints are
$\tau_{3}/m_{3}\leq5.51\times10^{-11}$ s/eV at $3\sigma$ CL. This constraint on
the decay parameter increases further if we assume that all the oscillation
parameters are measured precisely. In that case, the 3$\sigma$ constraint
obtained by using the synergy between DUNE and T2HKK is
$\tau_{3}/m_{3}\leq5.69\times10^{-11}$ s/eV. Again if nature prefers $\nu_{3}$
to be unstable and the decay width is $\tau_{3}/m_{3}= 2.2\times10^{-11}$ s/eV
then this combination can exclude the no decay scenario at more than $5\sigma$
C. L. . Although the CP sensitivity is not much hindered in the presence of
invisible neutrino decay, the measurements of $\theta_{23}$, as well as the
octant sensitivity, are very much affected. Octant sensitivity improves in the
lower octant in the presence of the invisible neutrino decay. However, the
synergy between DUNE and T2HKK improves the overall octant sensitivity in the
presence of invisible neutrino decay.
