In survival you need brains and brawn. Anyone who thinks he's into "survival" because he's read all the books, but is overweight, out of shape and isn't serious about getting back into shape with exercise, isn't really serious about survival. Your cousin needs to get serious about physical conditioning, it doesn't get easier as you age.

As for lightweight vs reliable, I put reliable/durable first and only look at weight when comparing items of similar capability. Lighter is better as long as reliability and durability are not compromised.

BTW, I carry an MSR Pocket Rocket w/ two fuel cannisters, but being in SOCAL I'm not subject to the much colder temps of Alberta, Canada where cannister fuel wouldn't do so well in winter. For that I'd switch to one of my Svea 123 stoves. I also carry a lot of water and an MSR water filter, because there's no snow to melt and any water I come across is suspect. My walking pack comes in at 12 lbs without water. With 5 quarts of water it pushes 20 lbs -- an easy load.