What are your goals here? You didn't mention any doses, but T3 and Clen stack is used for SERIOUS weight cutting. Thing is T3 does not discriminate between fat and lean muscle, it just burns tissue period.
It sounds like your friend has suggested the addition of Dbol to counteract the loss of muscle. This is not ideal, as the gains from Dbol will be mostly water and will go as quickly as they came. It also suppresses your natural test production, so it's almost completely worthless to run Dbol without running another androgen concurrently and several weeks after to help solidify the gains.
I've never used clen or T3 (and personally I will probably never fuck with T3), but from what I've read most people suggest Test Prop 50mg/day or 100mg/eod to stave off muscle loss while on a T3/Clen cycle.
You also did not mention an AI or PCT.
You're much older than me so obviously you can make your own decisions, and I'm not trying to be a dick, but overall I don't think you should do this because its clear you have little knowledge of these compounds or a proper post cycle therapy plan. Your buddy's knowledge is also suspect.