Razlo can heal the Vault Dweller, and offers a small amount of stimpaks for purchase, although he will only enter into dialogue with the player during daylight hours. At night, he will become very irritable if you wake him through dialogue, telling you to return in the morning. Also after the Vault Dweller completes the Make Poison Antidote quest he will accept any radscorpion tails and use them to create more anti venom for the Vault Dweller.
After Tandi is kidnapped, the Vault Dweller can talk to Razlo about it upon which he gives them two stimpaks and a fruit. If they come back at night and talk to him again about it, he will hand over the same amount of stimpaks and fruit again. [verified]