Lawyers need advice PLEASE

[aggieAXO]

My Family sold some property in Downtown San Antonio in 1996. We financed the buyer. In January, buyer fell 2 payments behind. Family lawyer sent a letter demanding payment plus lawyer fees by a certain date. The buyer sent a check for December's payment but not January's so again buyer is still a payment behind by late January. Another letter was sent demanding payment. My mother just received the January payment on Monday (almost 4 weeks late). February payment is due on the 15th. If he is late again and no payment is made -how long does this have to go on before we can foreclose on the buyer? What is the foreclosure process? He has never sent the lawyer's fees with the last 2 payments-can we sue for this money?

I would greatly appreciate any advice.

Thanks,

Karen