Edit: Curse my slow typing combined with a long post.
If I remember right, I think he typically runs the two masters and TH/SS termies in a Crusader, some foot slogging tac squads, and some ML Devastators.
What if you use a Shas'el with a relay like you did the last time I faced you? However, keep everything else in reserve. Do a modified ninja Tau list.
Place the Shas'el with a relay and shield gen. in cover or out of range of his Devastator squads if possible.
If he uses the bombs at the start, hopefully you can pass the invul save to keep the commander. If you fail the save, at least the only thing it took out was one suit. At best, he uses both on the Shas'el and he passes both.
If the commander survives to turn 2, I'd use the relay to bring on a railhead. I'm not entirely sure, but the railhead with a Disruption Pod will get the obscured cover save if he tries to bomb it. You can start using its range to take some pot shots at the LR to strand his CC Termies or take out a handful of marines. Another riskier choice would be bringing in the TL fusion team to take out the LR, but they could scatter too far away and then just be obliterated.
In turn 3, if he has used both of his bombs, I'd probably just roll like normal for the rest of the reserves. With your greater range and mobility, you can hopefully send fish towards any objectives while taking pot shots at his troops. You could use the relay again if you wanted. (Maybe for pathfinders in their fish. They can deploy in cover to be ready to help the rest of your army coming on next turn, and the fish will be able to be used next turn to help any deepstriking suits.)
Here's my thinking:
Keeping your army in reserve forces him to think about when and where to use his bombs. Since his masters must not move and cannot be in the LR in order to use it, his most obvious and easiest time to use it is the first turn; he can deploy his masters near the LR, drop the bombs, then hop in next turn. With one model to drop the bombs on, he must decided between the two following options.
If he uses them first turn, he can use the bombs to try and kill the Shas'el. (Which may cause your army to come in piecemeal). This hurts you less than he might hope because you have more transports, JSJ, and typically longer range. Plus, this means that one or both of his bombs went towards killing one model.
If he doesn't use them first turn, he can keep his masters standing still to use the bombs at any time, but that means that their cc abilities are wasted.
He can also have them get in the LR and advance. This makes it difficult for him to use the bomb for the rest of the game (since they basically stand still for two turns). Since your army is in reserve, they can try to stay far away from the LR so you have more time to destroy/immobilize it.
This can be more of a gamble, but I think it could work. It forces him to guess what you will be doing while you get to respond to the decisions he makes.
Hopefully I can watch the next time you face him.