@Fuhrer when you say “pumping 2 fighters into India” do you mean he is flying 2 fighters to India from UK, or that he is actually purchasing fighters in India? If the later is the case, that is rather poor purchasing on your opponent’s part, and you should exploit it. This means he will have very low fodder hitpoints at India.
If you’re running into problems pressuring India with Japan, this usually means you aren’t purchasing enough transports.
If your Japanese fleet is being regularly destroyed, that means either you’re not supporting it with sufficient carrier defense, or you’re trying to move it too far from home too quickly.
Operating out of sz 61 or sz62/60 is much safer than trying to do so out of sz 36, especially if UK is concentrating their air-power in India (and if they have ships surviving after a successful sz 37 attack, to help make that air-power more effective.) If you’re second carrier is destroyed, you should replace it immediately.
If your transport in sz 61 survives UK1, you are still in a strong position to crush India, but you have to back it up. Often times the Japanese player will stop short of purchasing enough transports to be effective. This is a minimum of 4 transports so you can transport the max production (8 ground) off Japan each round. But even this is on the low end. It’s better to have 5 or even 6 transports as the Japanese.
This allows you to push units first into Buryatia, to feint like you’re going to drive against Russia along the northern route, only to pick up some of those units the following round (with the purchase of additional transport capacity) and then swing south to pressure India.
Don’t be overly distracted by East Indies, Although it certainly sucks to lose this income to UK, its worse to let it deter your advance on India, while you get stuck out of position trying to recoup your loses in sz 37. If you keep pushing ground units into Yunnan via sz 61, this will allow you to threaten both India, and East Indies the following round, without putting your fleet at risk from India based fighters in the process. Even if Japan loses 2 of their starting fighters in sz 37, they still have 4 fighters and the bomber left, which is a lot of attack power, when combined with sufficient transport capacity.
I’d say your friend is on the right track that he needs fighters for India defense, but he should really be transiting them over from W. Russia or Archangel to India, rather than building them in India, both to cover Moscow and to give India sufficient hitpoints to face down a Japanese Burma push.
As for the 1 destroyer a round built at UK, you should be destroying these with German aircraft as soon as they hit the water. You can trade at advantage vs a single UK destroyer with 2 German fighters pretty easily. The DD only has a 1 in 3 chance to shoot you down, which means more often than not you can crush that enemy TUV at no loss to yourself. Better to sink a destroyer when its by itself, than waiting for it to stack up in a larger group.