It's not a love story,dear. It's just the kid wanting to learn to play mahjong and his friend's old man is the one who could.
For me the crush seems more in line with admiration for a kind, skilled (possibly retired professional) player. His friend seems to be the person with a romantic crush in the story. Like, when he talks about dating his friend’s Dad it reminds me of the time in TAWOG when Gumball mentions he “wants” to date Ocho because his uncle is Mario.
In other words, your assessment is the vibe I got.
ch 5 was really stupid. a really old, short and ugly guy being crushed on by a high school- not funny.