Pretty sure that combo wouldn't work, because the Q.Max will not cancel the second

+P (the most it will do is cut some of the recovery frames) and the

+P will knock down unless its cancelled with another

+P.
Edit:
Should also have mentioned that his most damaging non-DM combo s.C(1 hit)>

+P>

+P> d, d, d+K> d, u+P now does 'only' around 40%. If you have an SDM handy you should go for s.C (2 hits)>

+K > (Q.Max if in Extra mode) > SDM Tackle or Torpedo super, much more damaging. I suspect the Tackle super may do more damage but cannot be done in the corner (the subsequent charges will whiff and you get comboed for free, just like in '98).
- Also, the first hit of Brian Hammer negates projectiles. Dunno if it did that in the old '98.
- Saw in a match vid that Brian can now do d.B> d.A>

+PX3 but i haven't been able to do it myself. Not sure if the strength of the punch matters.
- IMO his toughest match up is against Yashiro/O.Yashiro. His d.C beats ALL your ground moves clean and jump D will almost always be faster than yours. Otherwise Brian does fairly decently against most top tiers.