1 mourning garments

1 to age

2 to deteriorate with age

3 old and weak

1 weak

2 feeble

1 organ failure

2 exhaustion

3 prostration (medicine)

1 to decline

2 to fall

3 to drop

4 to falter

5 a decline

6 recession (in economics)

1 life has its ups and downs (idiom)

1 weakening and close to exhaustion (idiom); in terminal decline

2 on one's last legs

1 old and weak (idiom)