I'm not a very good ost player, but i would go normal 3 gren and maybe double mg. Don't go for sniper imo, bcs you can't bleed a player that only has re squads. High chance he goes for zooks on one or two re's so i'd say double 222 isn't the best options. I gues a pak in combination with a flamer halftrack would still work, maybe even if the half track gives a lot of trouble you could go for puma in combination with the flame halftrack to keep the re's at distance as there bars become less good in that way. If he made a lot of 50cals i gues one mortar for smoke would help.
Command p4 is very good against infantry so it would rek his re's. Idk what he went as first tank?
Anyways hope this is a bit helpfull