How would you try to "convert" someone if the people of your religion that person was exposed to sucked?

for example, I know of someone who has a parent who became disabled @birth because of lack of medical care (was born in a camp and 0 doctor was avail. to help so the disability stemmed from lack of oxygen). The father, a devout person up to the point of only following eating rules (i.e., only eating non pork products), left the disabled mother during pregnancy and never gave child support...then fast forward to present day and the current religious people that person meets aren't inspiring either. The supposed hell everyone mentions is more inviting than to spend an eternity in the afterlife w/ those ppl. Doesn't someone have to be severely mentally ill to want to convert after those experiences? And doesn't the converter have some mental problems as well if they think it's a normal experience to accept as a past event and just join the same ppl. under the religious umbrella?