The easiest way to deal with Malak is to deal with the captured Jedi as soon as possible, meaning after he drains the first one, deal with the rest before you actually fight him. I usually play a darkside character, so It's either Drain Life or Death Field.
With a Jedi character, I think there is a power that will work the same way. Force Breach/Suppression, I think it's called.
At first, the only way I found somewhat easy was to use a double-bladed saber, with a Upari and Krayt Dragon pearl. Most likely in addition to the above.