Can a subcontractor sue general contractor for injuries from slip and fall accident on jobsite NY state

Has the subcontractor started an action against your brother. If he has it sounds like it should be covered under your brother's general liability insurance policy.

Assuming that the subcontractor was an independent contractor and not an employee of your brother he could potentially bring an action against your brother. However he would have to show that somehow your brother was responsible for the condition which caused his fall.

There is really not enough information here to determine if your brother could be potentially liable for ice at the work site. He could be liable for failing to provide a safe work site but that would depend on whether he knew or should have known about the ice condition which caused the fall.

He should contact a workers comp attorney in the county where he has his business. There are all kind of questions such as who controlled the work of the sub and where he fell. There is a potential problem that needs to be addressed before it gets out of hand.