Not likely , Arthur had tuberculosis which back then wasn't curable and was more or less a death sentence. In modern times it's treatable with antibiotics but medicine was pretty primitive back then. So it's unlikely he would have survived unless he didn't get the disease in the first place.
Didn’t the doctor tell Arthur to stay in warm and dry places
No. He was scripted to die. No ifs, ands or butts. He's dead Jim
If Arthur was mentioned or in rdr1 the rdr2 plot would’ve changed and this would have been the original plot
What if Arthur wore a mask when he contracted the disease in the mission money lending
....I dont get what youre going at here. Arthur dies, theres no stopping it or changing it. He either dies from TB or he gets shot. No matter what, he dies. And if Arthur never got TB, John would most likely be dead as well, as Arthur only helped him cause he himself was dead
Even if he somehow did survive the TB, he got shot in the shoulder and crawled to a cliff to die. If he had the will and strength to get back up, he probably would (I don't think Arthur is suicidal).