There is no way an insurance underwriter would sign off on this if the risk was too high. Is it without risk? Of course not. The risk isn't 0%, but it isn't 100%, either, and it's closer to 0% than it is to 100%. I'm certain every company that could potentially fly a helicopter to Maine Med's helipad has been made fully aware of the situation and necessary flight path. A helipad has similar operating procedures as any airport, and there is an ATIS broadcast for the helipad that all pilots must listen to before the even leave the ground to head to that destination. The ATIS broadcast includes all current relevant information, including current weather conditions, possible weather conditions that day, approach patterns, landing procedures, taxi procedures, etc. The pilots are in constant contact with air traffic controllers, who can update them in real time on weather conditions at the helipad. An air traffic controller in the tower at the jetport can also easily see the visual conditions at the helipad. There are sensors at the helipad to report conditions, and they can quickly reach the hospital if a visual inspection of conditions at the helipad are needed.
I know for a fact that Lifeflight and other carriers have an alternate landing location at the jetport if there are safety concerns with the helipad (i.e. wind, ice, snow, fog, heavy rain, thunderstorms, etc.). If they have to divert, there are procedures for an ambulance to be waiting for them at the jetport when they land.
Of course human error is also possible with any flight, be that helicopter or airplane or hot air balloon, but as an insurance underwriter myself, I am certain the risk has been evaluated thoroughly, factoring in all of the safety procedures in place, concerns over rapid weather changes , and even the potential for human error by a pilot and/or crane operator.