Lease expiration - Chicago tenant

[Jehanzeb Beg]

Tenant lease is expiring on may 31st. It’s family with husband/wife and a brother in law. They split rent. I wanted to ask them if they want to continue to stay month to month or leave at the end of lease term. The tenant I’m in contact with has been ignoring my calls and saying he’s busy and told me to call his brother in law. I got in touch with the brother in law who say he wants to stay. I told him I’m willing to keep the rent same as long as they abide by few small things I ask for. Such as if they are going to be a day or 2 late on rent, they need to notify me. They pay on time except the last 2 times I had to ask for rent and no response from the tenant. He just ended up paying a day or two late. The brother in law mentioned he pays the other guy his share prior to end of the month.

I’m asking for advice on how to move forward. I asked the other guy(husband) to contact me but he hasn’t. I have to know before end of the month or send a letter for vacating the property after lease is up.

What should I do in this case? Send letter just in case and wait for the other guy to call me?