[Imp]

Well you are very persistent in what is very much an uphill struggle so some thoughts.
As said if possible cluttered terrain not open & despite being a meeting a slow move out till his air is dealt with if has helos is more than acceptable.
Need to fight 2 battles for the air battle your killers are RBS 70 manpads TOR-1s & 80 Range AA guns as helos have 60 vision. All other AA assets are deterents that might get lucky while these guys get in position. What you buy depends on game size if you think he might buy SEAD etc the out gessing game.
Keep TOR-1s well back & relocate often to avoid arty if vision is high with dust trails a few trucks in your arty park can make false dust trails when they move.
The AA guns consider moving some forward if terrain allows in first couple of turns.
Can use some as deterents if need when other AA moves but generally cut range down to 65-70 or even less if can risk it. Now if he leaves a helo within range you can take multiple shots in your turn rather than playing the max range dance. AAA is the one set of units its worth micromanaging ranges on to sucker people into the kill zone vs helos.
The other aproach is half a dozen mobile at least EW 5 SAMs, hit chance is not good its hard work firing relocating rearming but the odds will get them eventually.

The ground battle I would generally do low key till his air is at an acceptable level the worst problem with those helos in my view is there scouting ability if vision is below 60, start every turn by locating his helos with your radar AA so you can get an idea of what he can see otherwise any ambush is probably blown.
Your tanks are totaly ouclassed if have any armour use only to snipe at his APCs as have MGs only or for infantry support.
Your infantry do not have particulary good RPGs so gang up on tanks. Need to be able to draw fire or whatever to let you get in position from flanks rear or to assault.
Cheap APCs can help this if he leaves tanks open draw fire & then send them in as a mech assault. 2 Squads who recieve no or minimal fire should take it out normally.
Tanks are a lot easier to kill if suppressed or damaged so unload use the W key to fire your RPG. Only if it still survives assault it with your last shot once its heavily suppressed. RPG teams do not work that well in mech assaults to few shots & men to asault so use them to fire at the tank in the first place if possible. The hard thing with planing these is remember the tank could pop smoke at any time & ruin your plans.
Good luck.