Cat cant live outside and needs sterilizing to live inside of our house

We had a cat that we introduced to our house when he was 3 weeks old with no mother and a his 2 front paws are a bit defective. We tried to encourage him to go outside from time to time to get used to living outside but he never did. when he was 2 years old he became more aggressive when he smell other outdoor cats or hear them which made him difficult to keep, one day he left home after scratching my nephew on his face after hearing other male cats, and lived outside for 2 months, we kept looking for him everyday, suddenly he came back very thin and thirsty and with injuries on both of his front paws, the doctor said that he cant live outside with his pawns which cant handle rough lands, so he only can live in a safe keep such as homes or shelters, and our country doesn't have shelters for cats. So the only solution is to neutralize him if we want him inside, but we couldn't do it fearing that its haram, what should we do.