Is the dipole horizontal? If not how far is it separated from the vertical antenna? Since both are 1:1 SWR they are resistive 50 ohm loads. Parallel them with the T and you land up with 25 ohms and a 2:1 SWR. This load can be transformed to 50 ohms if you need. How will it work? Probably not as good as the antenna out in the clear by itself but there will be some times where it may outperform either one by itself. Experimenting is good.