Can a young boy adopt personality qualities of his deceased grandmother? example preferance for her music, ...?

the reason i ask its because i have a friend who suffers from aspergers, he is 19 yrs old now, but his parents abandoned him when he was 5 since he ually abused his younger sister, than he started acting violently towards animals and people. that changed dramaticlly after he was adopted by an old lady who seemed to nurture him and teach him to be responsible, ect. but when he turned 12 she ped away and than he was diagnosed with schizophrenia and he seems to act alot like her now, his preference in old music from the 1930s , he even seems to be emotionally mature for his young age, also he prefers older women, ect...how is this psycologiclly possible and what will become of this person in the future? will he find himself? or will these traits be part of him forever , i tried talking to his shrink and he just told me that his case was complicated and to think carefully about the consequences before getting involved with him. I am 31 yrs old and madly in love with him. He seems so tender, sweet and understanding, he admits he isnt a saint, but he wants to love and take care of the person he loves. i am divided between reason and unconditional love. some advice would be great. thank you and god bless.