Help Milkshake get vet care!

Milkshake is our 4 year old cat that went missing on September 15, 2019.  After 3 months and 8 days we got a call that someone had found him. Our little boy was alive, but unfortunately he is in rough shape and will have many vet bills to be paid.
He will be in the animal hospital for currently an unknown amount of time as he has an infection, and a gaping hole in his body. His harness, which aided in him being found, unfortunately became embedded in his skin along with the tags attached to it. He weighed 16 lbs when he got lost and now he is less than 6 which is over 70% of his body weight. Due to the open wound and everything else wrong, he will be on IV fluids for a couple days at the least. 
Were looking at vet bills as high as $3500, possibly even higher. The vet says the treatment and the cost will have to be taken day by day based on what he needs done, but this is the lower end of things.
We have already put down $1000 deposit so that they can begin treatment however due to limited incomes we could really use some help.
We were convinced he was dead. It had been so long and our neighbourhood is riddled with coyotes. We're so happy to have our little boy back, now we just need to get him the best care possible.
ALSO, ANY EXTRA MONEY RAISED WILL BE DONATED TO THE OSPCA FOR THE HOLIDAY SEASON
UPDATE: We have raised the go fund me by a $500 dollars as we’ve realized we will not be able to cover anything more than the two follow ups with the current amount. We are currently unsure whether we will need other follow ups or more food. There will be a financial breakdown in the updates of the gofundme so that people understand. Any extra will still go to the OSPCA!