HOW DO KNOW ABOUT TU.154 (RUSSIAN JET)SAFETY BACKGROUND?
Statistically It's not that great but as the aircraft is often flown in poorer countries with little regulation, the reasons are mostly down to poor maintenance or low ability in the flight deck ether through lack of skills, training or unsatisfactory attitude. If properly flown and maintained, its about as safe as any other aircraft from its era including American and European built aircraft.
1 month ago iranian civil aviation organization prohibited operation of this for ever in iran.
Probably due to political reasons as the general state of most commercial aircraft in Iran are below what most countries would deem as acceptable, mainly due to the fact that trade sanctions forbids the sale of aircraft spare parts to Iran. Most of Iran Air's aircraft are still blacklisted and banned from entering European airspace.
Sorry to hear of your loss.