Quando Ron salvou Harry (naquele tempo Harry estava encontrando a espada de Godric Gryffindor) no lago, naquele momento ele estava absolutamente saudável porque ele puxou Harry para fora do lago com seus braços.
Considerando isso, acho que ele estava muito bem antes da guerra.
E se ele ainda não estava bem, Harry não lhe diria para destruir o medalhão com a espada:
Ron raised the sword in his shaking hands: The point dangled over the frantically swiveling eyes, and Harry gripped the locket tightly, bracing himself, already imagining blood pouring from the empty windows.
Outra linha do Relíquias da Morte :
Nothing but the shock of hearing that voice could have given Harry the strength to get up. Shivering violently, he staggered to his feet. There before him stood Ron, fully dressed but drenched to the skin, his hair plastered to his face, the sword of Gryffindor in one hand and the Horcrux dangling from its broken chain in the other.