Boga came through the Blues academy with Abraham before leaving permanently last year for Sassuolo.
The Marseille-born Ivory Coast international joined Chelsea at 11 years of age and came through the Cobham academy alongside several of the Blues youngsters now getting their first team chance this season under manager Frank Lampard - including Abraham.
The emergence of the England international as a force for Chelsea has caught the imagination of football fans across Europe and Boga took questions last week from French reporters about his former teammate.
He told Foot Mercato: "For those who do not know him, it's impressive what he does. I've known him since we were little, we are of the same generation 97 in Chelsea. I know his potential. He has always been a scorer, scoring 20 to 25 goals per season in all categories of youth.
"So what he does today does not surprise me. I am very happy for him."
With Chelsea, Boga twice won the FA Youth Cup before spending three seasons away on-loan with Rennes, Granada and Birmingham City ahead of cutting all ties last year. However the midfielder, now 22, confesses seeing his former youth teammates making it at Chelsea has him thinking of a return to London - in the long-term.
Of his own plans, Boga added: "Everything in its time. It certainly was not the time for me to play Chelsea. I always keep it in a corner of my mind. If I continue to do what I do, work hard, maybe I'll go back one day."
- updated December 2