Hmm...I don't know. I think contractions like "He's" is assumed to be "He is." I can't think of an instance where I would say "He's" instead of "He was" that would sound natural.
Stick with past tense. Everything surrounding it is past tense too and it won't sound like he's dead unless you use "had been."
She smiled fondly at the picture of Benny displayed on her night stand. He was really one of her favorite people--funny and charming, sweet and loving.
See, even if he's offstage, it doesn't seem like he's dead. Now if it were:
She smiled wistfully at the picture of Benny displayed on her night stand. He had really been one of her favorite people. He had been funny and charming, sweet and loving.
See the difference?
You're all good.