Should Mercy Killing be Legalised

"I used to cry for I had no shoes to wear until I saw a man with no feet "
A month back, a visit to a Mentally retarded and an Oldage Home, made me realize that i was so very lucky to be born as a very normal baby.I had this habit to generally crib about things(as many of us have)which i have stopped to quite an extend.This place is named as "PREM DAAN"which is situated in Airoli(Navi Mumbai) where u can actually see small mentally retired children ,it really got tears from my eyes.i was just feeling helpless.I did feel wat was i doing there...so many questions in my mind.Kids thr just come and hug u..Hats off to Mother Terrasa who really gave her life for the unknown..How much of us really can do that.Ok max most us would think abt donations but can we really go and help these ppl or such institutions.Donations also dont work unless we are assured that the money donated is being used for the same purpose.I also feel that nowadays u cannot quit ur job and do that but yes secure a proper financial background and help in our own wayzz.Each of us are so damn lucky to be the person that we are today.
Also the ppl working thr are doing a gr8 job.Thare are children who are very violent also.one really needs patience to do the job whole heartedly.
This also makes me to think abt Mercy Killing..Should it be legalised...Ok we can answer very easily a "YES" coz does the person really needs to lead a life thats so painful specially for a person above 60+ or the answer would be "NO" coz u might never know the person may come back and lead his own life.
There could be various situations where a possibility of a yes or no would suit.

• A YES would If the person himself does not want to lead such a dreadful life
  
• A NO because we should not leave hopes for the person,y give up hopes when Medical science is coming up.
  
• Who has the right to take such a desicion at the first place( Persons near & dear ones)
  
• Even if the desicion is made by the person himself, is he in the proper state of mind.
  

Somehow i feel it should not be legalised.but still sometimes when u come across such situations such pains it really makes u think if it should be legalised......