be taken with a pinch of salt	when sth is considered untrue
at death's door	about to die
off colour	unwell
be full of beans	very lively and energetic
go downhill	get worse in health/quality
be nothing but skin and bone	very thin
be a shadow of one's former self	weaker or less capable than one used to be
up and about	active after an illnes
as strong as an ox	very strong and fit
ripe old age	very old age
kick the bucket	die
alive and kicking	still active and alive
touch and go	uncertain
the writing is on the wall	a sign of danger
hold your own	manage despite difficulties
grin from ear to ear	smile broadly
there's life in the old dog yet	one's still physically and mentally energetic despite old age
as blind as a bat	blind or unable to see well
have one foot in the grave	be near death
run out of steam	lose the nergy that one had previously