Now you know where Mek got his moustache. It was Rumble's all along.
When Mek feels down, is mostly his father who's always there cheering him up. Mek's definitely a "dada's child". From the very beginning, Rumble was the one encouraging him to try new things, to work in the farm, to study magic, anything that could staop him from feeling useless due to his condition, while Applebloom was always overprotecting him just so he wouldn't get hurt.
Rumble helped him grow strong and confident, or he would if it wasn't because of Applebloom. Since the very beginning she felt guilty, she thought that the fact his child was born without one of his legs was her fault, because she couldn't stop working and just rest for a few months. Of course it wasn't her fault.
While Rumble encouraged him, Applebloom was always worried, "he could get hurt, he's not like the other kids". Of course it wasn't her intention to make his child absolutely unsecure of everything he could ever think of, but she did.
Thankfully Mek has friends that encourage him to explore what he can do and to be better everyday. He's lucky there are ponies like Max and Skipper around him.