If an employee cannot make it to his shift, he is not reliable. Talk to him and tell him that you appreciate the work he’s has been doing and how he’s a good employee but you need someone reliable and can consistently make it ti work. Tell him to sort his things out and reach out to you when he’s in a better personal situation.

Go out and start looking for someone. Do not wait for him to come back and if he does come back, bring him on only if you need the extra help. Do not feel personally obligated to him. He’s got too much baggage. Your business first and foremost.