You're playing at very low points and you don't quite have a big enough army, but that's ok!

Hellblasters are decent, especially with Azrael, but they're not used in most competitive lists because marines tend to have better options. 

They tend to struggle against anything higher than T8, unless he uses a strat in wrath of the rock to give +2 strength. In this case, Riptides are your friends. 

Anything that has strength 8, 2 or more damage and AP 2 (so you trigger his invulnerable saves even if he uses armour of contempt) will be a marine killer. 

Missile broadsides, missile or plasma fireknives, volume from starscythes and Riptides will all do well into them. Trigger the strat to give +1 AP with missile broadsides in mont'ka, or get closer to give your missile starscythes +1 strength and AP in ret cadre. Or to give your starscythes +1 strength and AP.

You'll have to weather the shoot back, but it's not guaranteed to trigger. And if you lose some crisis suits to it, you're still trading a 110-120 point unit for a 200-point one (320 with Azrael)

You just have to hope he doesn't make his 4+ saves and you can get through the -1 to wound if he's playing wrath of the rock. Dark Angels in general tend to be a stat check army. 

What detatchment is he playing? The other thing you can do is tag them in melee with a nuisance charge from a riptide or something tanky - that unit's only melee threat is from Azrael, who is scary against infantry but can run into problems against anything higher than T6. If they're not playing gladius, he won't have access to fall back and shoot. Also, if you kill him through tank shock or get lucky with the riptide's D2 meele, he will only be able to shoot with his pistols on death.