I labbed out some stuff in regards to Brawler's custom 2 Up-B for Cat because it's so clearly not ok, and she suggested I post it here too. So I'll give you the summary, and you'll basically just have to trust me that I'm right XD.
If you get grabbed always immediately DI toward Brawler so that when you get D-thrown you will end up above him.
After the D-throw, regardless of whether you DI'd it correctly or not, immediately DI diagonally up and away from Brawler. This is because you want to always DI Fair up and away as it will give you slightly more time to avoid the Up-B2 that will no-doubt follow Fair, which will allow you to airdodge the Up-B2 where you otherwise would not have been able to.
If you do get caught in Up-B2, you have enough time to react to the fact that you are in Up-B2 so you don't need to pre-plan your DI. Simply react and hold toward brawler i.e. away from the side blast zone you are going to be launched toward. This will keep you the furthest away from the side blast zone while also keeping you up high enough to recover after you've survived (if you survive).
Once you're on a high enough percent such that a raw Up-B2 will kill you, D-throw follow ups can be airdodged, but this doesn't mean you should. If it means taking an Uair, just take it. What you want to avoid is having your airdodge baited and punished with an Up-B2. So what other option should you consider other than airdodge? Well,
Nair is our way of beating Up-B2 so long as we have enough time to actually get the hitbox out. You will use Nairs in conjunction with FFing to help you land instead of airdodging in conjunction with praying.
Brawer's Up-B2 will slightly out-range our Nair from in-front, so if the Brawler spaces it and times it just right, it will beat Nair. However, Nair will beat Up-B2 from above, period. If the Brawler comes up at you from a diagonal angle (even if it's just to avoid you FFing and them missing entirely), Nair will either win or trade. When considering that the only way Brawler can beat Nair or trade with it is to line the multi-hitting move up such that one of the kicks comes out at just the right time, and considering also that you can actually raise your chances of Nair beating the Up-B2 by moving towards Brawler and/or fast falling the Nair (making it that much harder for Brawler to line up one of the kicks), we've got a winning option here. In the event that you do trade, you'll take 2% only and regain control first with Brawler taking 6% even if it's the sourspot of Nair, so arguably trading is a win for us too.
