I frankly think this guys mother was a bit harsh with her son.
Ask anyone at any age if they can G-d forbid deal with such a challenge and the answer will likely be no. Yet when someone is unfortunately thrown such a curveball they usually get on board and somehow manage to deal with it.
It may take a while but shy people gain confidence to talk to doctors, make decisions and grow from the experience. Of course, especially in the beginning they will need medical advice, chizuk etc. but eventually they get a handle on the situation.
Even something as simple as asking for help takes maturity and shows one is realistic as to his capabilities. Unfortunately some people do break down — but I wouldn’t pin it on age as much as on emotional strength/bitachon and of course siata dishmaya, which we all need at every age even when the going is smooth.
If someone chas vasholam gets sick himself, married or not, is he prepared to deal with it? So maybe he should have never been born? My point is we hope to never be challenged like this but it’s not up to us to plan and be fully prepared for every worst case scenario.