Apologies for being pessimistic but it's not gonna matter at all. It might even be worse if he does win. Half the Democrats are already planning independent runs. The other half will do everything in their power to sabotage his run from inside the party. If he does win the primary then the whole New York Democratic apparatus is going to withhold its support for him and will quietly support Cuomo.

If he somehow manages to win in the general election despite this then the whole bureaucracy will just cease to cooperate with him and ever single issue will be blamed on him. The papers will say "The People's Republic of NYC, another failure of socialism". He's an AOC/old school DSA guy which means he's unlikely to have the guts to seize and wield power the way he would need to because the norms are too important.

This is the problem with the DSA program that they actually carry out. They are able to build electoral machines that win elections but they're toothless at the end of the day. When they get into office they are simply not compatible with the bourgeois state as it exists and the actual power brokers in the DSA are unwilling to smash any part of the capitalist state with mass action.

Edit: if I were to offer a solution rather than just a criticism I would say after the primary he should run for mayor regardless of whether or not he wins and he should spend the entire campaign explaining to New Yorkers that if they want things like universal childcare, free busses, and rent freezes then they need to make the system untenable until they are won. He needs to explain to them very explicitly that no politician can or will deliver on those things and all the forces of the state are aligned against them.