Huge mushy lump on cats head?

Our neighborhood stray cat has this lump on his forehead and it’s mushy, we can’t afford to take him to a vet though. It seems to be increasing in size. He’s a bit aggressive as he isn’t fixed so we’re not sure how he would take to us trying to work on it, but we’re willing to try. Any advice?

Our neighborhood stray cat has this lump on his forehead and it’s mushy, we can’t afford to take him to a vet though. It seems to be increasing in size. He’s a bit aggressive as he isn’t fixed so we’re not sure how he would take to us trying to work on it, but we’re willing to try. Any advice?