If you strongly suspect that somebody you know has Asperger syndrome, do you tell them what you think or not?

Hi, 

My name is John Gaffen, I don't have Autism, but I very strongly suspect that  someone I know very well, has undiagnosed  Asperger's Syndrome. This person was married to my sister, who sadly passed away back in April of this year.  He has all the classic  characteristics of this syndrome and has even mentioned to me directly that he has no real friends.  I have known this person for many years and  it has been extremely difficult  sometimes to  get along with my brother-in-law.  This person is  now in his  70's,  he has a very high IQ,  but his social interactions can be very awkward and one sided. He gets very focused on very narrow  areas of interest and or conversations and finds it difficult  to empathize with other people at times. He uses his considerable intelligence to try and navigate around some of these issues, but not always successfully. 

My question is 1). Should  I tell him what I think, that he probably has Aspergers,   2). If so, how should I approach or  I go about doing this  3). What other advice should I offer to him if I go ahead and tell him?

This is a difficult one, as I am worried about doing more harm than good.