As IndraSunrise said, avoid battles. Unfortunately, if you started the war (which you said you did) and you cannot win, the AI may be brutal and demand near 100% warscore. The key is to hold out until their war enthusiasm becomes negative or less than 20. Less than 20, you can get away with losing only a couple provinces. If it's negative and you have most of your land in tact, you can get out with a draw.
Honestly, when I look at your screenshots, I would take your 14k stack down through your ally Balluchistan, and sit with your allies 6k stack on Sind's capital. Hopefully one of three things happens.
1) Your fort halts Sind/Delhi's armies from reaching Sind's capital before your stack arrives. I don't think it will since it's only one, but may detour them long enough to by time.
2) The AI ignores the stack on Sind's capital until your capital falls.
3) The AI splits their stacks and you are able to fend off the one that goes after that 6k stack on Sind's capital.
If you can get Sind's capital to fall, you will be able to work out a white peace at worst most likely as their war enthusiasm instantly drops and your war score will rise. Also, you have very slight naval supremacy. Attempt to blockade Sind's capital's port. Not sure if 10 barques, 2 light ships, and a transport are enough, but if you can get their port blockaded enough, then they will go from -35% to -21% instantly for the siege and that will make the city fall a lot faster.
To summarize, in my opinion, these should be your goals.
1) Attempt to blockade Sind's capital. If it fails, send your ships back to port and leave them there.
2) Join up your stack with your ally that's besieging Sind's capital.
3) Sit on that capital until it falls.
4) If you can get the capital to fall, instantly sue for peace. See if you can sign an independent white peace with Delhi (doubtful).
5) If you can sign a white peace with Delhi, then finish off Sind.
6) If you cannot, which I doubt you can, then accept whatever white peace or slight victory you can achieve before those enemy stacks wipe yours out.
Also, I just noticed you have four mothballed forts... Turn at least some of them back on. They may distract the AI and again get them to split stacks. You are also doing alright financially. Not sure how many loans you have, but build a few mercenary units if necessary to aid in making Sind's capital fall. Don't be afraid to go a little into debt early in game. Especially if it can cause you to win a war. Take 10% war reparations in every war you win if possible. It really helps the coffers.