Akon's Brother Abou Thiam -- Baby Mama Wants More $$$ ... He Says Hellll No

Baby-mama drama must run in the family ... Akon's lil bro Abou Thiam -- a huge record exec -- is asking a judge to shoot down his baby mama's demand for more cash ... despite his fat bank account.

According to legal docs filed in Georgia ... Abou agreed to shell out $3,000 / month in child support to a woman named Ariel Hakim back in 2010. The pair has one daughter together.

But Ariel recently filed new docs, asking the court to up Abou's monthly payment -- claiming their kid costs more money now and not only that, she says Abou's income has increased dramatically.

FYI -- Abou is the VP of Def Jam Records and in docs filed in 2010 he listed his income as more than $38,000 PER MONTH.

Abou fired back at Ariel's request on Nov. 8 -- and asked the court to LOWER his monthly payments, despite the fact that he's pulling in more dough (as admitted in docs).

Abou makes the argument ... Ariel moved their daughter from Georgia to Florida without giving him the proper 30-day notice -- which he claims violates his visitation rights and creates a greater financial burden, due to the travel costs.

He's asking the judge to deny Ariel's request and hold her in contempt of court.